The systems within the body associate with each other to keep the organism in a healthy state. Though every system of the body exhibits particular functions, they all are dependent and inter-associated with each other. The nervous system controls various systems of the body.
The muscular system comprises distinct kinds of muscles that permit motion, produce heat to sustain a temperature of the body, does contraction of the heart, and move the food via the digestive tract. It comprises three kinds of muscles, that is, smooth, skeletal, and cardiac muscles.
The muscular system coordinates with the nervous system and does various functions. The receptors found in muscles instruct the brain with the information regarding the movement and position of the body. The brain monitors the contraction of skeletal muscle. The nervous system monitors the speed at which food passes through the digestive tract.
An unknown material has a mass of 5.75 g and a volume of 7.5 cm3.
What is the density of the material? Round to the nearest tenth.
A. 0.8 g/cm3
B. 8 g/cm3
C. 0.7 g/cm3
D. 1.3 g/cm3
Hey there!:
Mass = 5.75 g
Volume = 7.5 cm³
Therefore:
Density = mass / volume
D = 5.75 / 7.5
D = 0.7 g/cm³
Answer C
Hope that helps!
At the end of an experiment, the product is a mixture of the starting material, which is benzoic acid and the product, which is benzaldehyde, both of which are dissolved in diethyl ether. the reaction mixture is best separated by
a. extraction with a solution of hydrochloric acid, separating the layers, followed by drying and evaporating the organic layer.
b. extraction with a solution of sodium bicarbonate, separating the layers, followed by drying and evaporating the organic layer.
c. drying and evaporating the organic layer.
d. extraction with a solution of sodium bicarbonate, separating the layers, add diethyl ether to the aqueous layer, extracting with a solution of hydrochloric acid, filtering and recrystallization the solid product.
Answer:
b. Extraction with a solution of sodium hydrogen carbonate, separating the layers, followed by drying and evaporating the organic layer.
Step-by-step explanation:
The ether solution contains your product, benzaldehyde, and some starting material, benzoic acid, the purification steps are:
Extract with a solution of NaHCO₃. The ether layer contains benzaldehyde, and the aqueous layer contains sodium benzoate. Separate the layers. Keep the ether layer. Dry the ether solution. Distill the ether (boiling point 35 °C) and purify the benzaldehyde (178 °C) by steam distillation.a. is wrong. Extraction with HCl will not remove much of the benzoic acid.
c. is wrong. If you evaporate the organic layer, you will have a mixture of benzaldehyde and benzoic acid.
d. is wrong. If you work with the aqueous layer, you will end up with benzoic acid,
Carbon-14 if often used for radioactive dating, but it has its limitations. Uranium-238 or lead-206 are most often used to date rocks.
Why would U-238 or Pb-206 be more useful than C-14 when dating rocks?
A) Rocks do not contain any carbon for dating purposes.
B) Carbon-14's half-life is much too long to use for dating rocks.
C) The half life of carbon-14 is about 5700 years and is too short date rocks.
D) Carbon-14 is only found in living things; it can only be used to date remains.
Answer:
C) The half life of carbon-14 is about 5700 years and is too short to date rocks.
Step-by-step explanation:
The practical limit for carbon dating is about nine half-lives (50 000 yr).
At that point, the amount of carbon remaining has dropped to about 0.2 % of the original amount.
The experimental uncertainties involved become so large that carbon dating is no longer reliable.
Most rocks hundreds of millions or even billions of years old.
Any radioactive carbon would have long since decayed to unmeasurable levels.
A) is wrong. Many rocks contain carbon, but they are so old that the amount of radioactive carbon has dropped below measurables.
B) is wrong. The half-life of carbon is too short to use for dating rocks.
D) is wrong. About 20 % of the carbon in rocks comes from living things that were embedded in layers of mud.
===============
Uranium-238 and lead-206 have half-lives of 4.5 × 10⁹ yr, which is about the age of the Earth.
Even the oldest rocks would still have half of their radioactivity, and younger rocks would have more.
Thus, U-238 and Pb-206 are ideal isotopes for measuring the ages of rocks.
how can you tell a Ca(NO3)2 solution from a Zn(NO3)2 solution?
You can distinguish between a Ca(NO3)2 solution and a Zn(NO3)2 solution by performing a precipitation reaction test. Adding NaOH to the solutions will result in the formation of a white precipitate in the Zn(NO3)2 solution, but not in the Ca(NO3)2 solution.
Explanation:You can tell a Ca(NO3)2 solution from a Zn(NO3)2 solution by performing a chemical reaction test called a precipitation reaction. When a solution of NaOH is added to a Zn(NO3)2 solution, a white precipitate of Zn(OH)2 is formed. However, when NaOH is added to a Ca(NO3)2 solution, no precipitation occurs.
This is because Zn(OH)2 is insoluble in water and forms a white solid precipitate, while Ca(NO3)2 does not form a precipitate with NaOH as calcium hydroxide is soluble in water.
Therefore, by observing the formation or absence of a white precipitate when adding NaOH to the respective solutions, you can distinguish between a Ca(NO3)2 solution and a Zn(NO3)2 solution.
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To distinguish between a [tex]Ca(NO\(_3\))\(_2\)[/tex] solution and a [tex]Zn(NO\(_3\))\(_2\)[/tex]solution, one can perform a series of qualitative tests and observations.
Here are some methods:
1. Flame Test:
Add a few drops of the unknown solution to a flame using a clean platinum or nichrome wire. Calcium ions[tex](Ca\(^{2+}\) )[/tex] in [tex]Ca(NO\(_3\))\(_2\)[/tex]will impart an orange-red color to the flame, while zinc ions [tex](Zn\(^{2+}\))[/tex] in [tex]Zn(NO\(_3\))\(_2\)[/tex]will not produce a characteristic flame color.
2. Precipitation Reactions:
a. Add a few drops of ammonia solution to the unknown solution. Zinc ions will form a white precipitate of zinc hydroxide,[tex]Zn(OH)\(_2\)[/tex], which will dissolve in excess ammonia to form a clear solution due to the formation of tetraamminezinc(II) complex, [tex][Zn(NH\(_3\))\(_4\)]\(^{2+}\).[/tex]Calcium ions will not form such a complex and will remain as a precipitate of calcium hydroxide, [tex]Ca(OH)\(_2\).[/tex]
b. Add sodium sulfate solution to the unknown solution. Calcium ions will react with sulfate ions to form a white precipitate of calcium sulfate, [tex]CaSO\(_4\)[/tex], which is insoluble in water. Zinc sulfate, [tex]ZnSO\(_4\)[/tex], is soluble in water, so no precipitate will form in the presence of zinc ions.
3. Conductivity Test:
Both solutions will conduct electricity due to the presence of ions. However, the conductivity of the solutions will not help in distinguishing between the two since both have similar numbers of ions when dissolved in water.
4. Solubility Test:
Both[tex]Ca(NO\(_3\))\(_2\)[/tex]and [tex]Zn(NO\(_3\))\(_2\)[/tex] are generally soluble in water, so this test may not be conclusive. However, if a precipitate forms upon dissolving the salt in water, it could indicate the presence of calcium, as some calcium salts have limited solubility in water.
5. Complexometric Titration:
Using a chelating agent like EDTA (ethylenediaminetetraacetic acid) in a complexometric titration can differentiate between the two. Zinc ions will react with EDTA to form a stable complex, while calcium ions will not react as readily under the same conditions. This can be indicated by a suitable metal ion indicator such as Eriochrome Black T for calcium or xylenol orange for zinc.
By performing these tests, one can determine whether the solution contains calcium nitrate or zinc nitrate based on the observations made during each reaction.
How many moles of oxygen gas (O2) are in a 2.50 L container at standard temperature and pressure?
2.24 x 10^1 mol O2
1.12 x 10^–1 mol O2
2.50 x 10^0 mol O2
5.60 x 10^1 mol O2
Hey there!:
1 mole O2 ----------------- 22.4 L ( at STP )
( moles O2 ) -------------- 2.50 L
moles O2 = 2.50 * 1 / 22.4
moles O2 = 2.50 / 22.4
moles O2 = 1.12*10⁻¹
Answer B
Hope that helps!
1.12 x 10^–1 mol O2 moles of oxygen gas (O2) are in a 2.50 L container at standard temperature and pressure. Therefore, option B is correct.
What do you mean by mole ?The term mole is defined as the amount of substance of a system which contains as many elementary entities.
One mole of any substance is equal to 6.023 × 10²³ units of that substance such as atoms, molecules, or ions. The number 6.023 × 10²³ is called as Avogadro's number or Avogadro's constant.
The mole concept can be used to convert between mass and number of particles.
1 mole O2 = 22.4 L (at STP)
(moles O2) = 2.50 L
moles O2 = 2.50 × 1 / 22.4
moles O2 = 2.50 / 22.4
moles O2 = 1.12 × 10⁻¹
Thus, 1.12 x 10^–1 mol O2 moles of oxygen gas (O2) are in a 2.50 L container at standard temperature and pressure, option B is correct.
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In an experiment, 132 grams of potassium bromide was dissolved in 100 grams of water at 70°C in 1 minute. Which of the following will most likely happen if the sample of potassium phosphate is dissolved in 100 grams of water at 20°C?
1) the number of collisions between particles will increase
2) the number of collisions between particles will remain constant
3) a greater number of particles of the sample will dissolve in 1 minute
4) a fewer number of particles of the sample will dissolve in 1 minute
The correct answer is option 4, that is, a fewer number of particles of the sample will dissolve in 1 minute.
This is mainly because usually the solubility and the rate of solubility of the salts in water enhances with the increase in temperature, that is, the more the temperature, the faster and higher will be the number of particles that the water can dissolve. Therefore, at 70 degree Celsius more particles will get dissolved in water in 1 minute than at 20 degree Celsius.
Answer: its (4) a fewer number of particles of the sample will dissolve in 1 minute
Explanation:
got it right on my test
A sample has a hydrogen ion concentration of 1 × 10−2. What happens if the hydrogen ion concentration increases? The acidity decreases. The pH decreases. The hydroxide ion concentration increases. The solution becomes more basic.
Answer : The correct option is, The pH decreases.
Explanation :
As we know that,
pH : It is defined as the negative logarithm of hydrogen ion concentration.
Mathematically it is represented as :
[tex]pH=-\log [H^+][/tex]
According to the question, when the concentration of hydrogen ion increases then the value of pH decreases and the acidity of the solution also increases that means the solution is more acidic in nature.
Hence, if the hydrogen ion concentration increases, the pH decreases.
Answer:
The pH decreases
Explanation:
Hello,
pH is mathematically defined via:
[tex]pH=-log([H^{+} ])[/tex]
Since at the beginning, the concentration of hydride ion is 1e-2M, the pH is:
[tex]pH=-log(1x10^{-2} )=2.0[/tex]
If it is increased, lets suppose to 1.1e-2, the new pH turns out into:
[tex]pH=-log(1.1x10^{-2} )=1.96[/tex]
So the pH decreases, which means that the acidity increases as well.
Best regards.
What is the percentage of water in the following compound?
Sodium carbonate decahydrate, Na2CO3 • 10H2O
% by mass H2O
which elements does sulfate ion contain?
Answer: Sulphur and Oxygen
Explanation: Sulphate ion is [tex]SO_4^{2-}[/tex]. It is polyatomic ion which is formed by the combination of sulphur and oxygen elements in the ratio of 1:4.
It is negatively charged species and thus is named by the name _ate at the end.
It usually exists with positively charged species to get stable. eg: ferrous sulphate ([tex]FeSO_4[/tex])
how is an unknown oxidation state of an element within a compound determined?
a. it is determined from known oxidation state of an element within a compound determined
b. it is always the same as the most likely oxidation state
c. it will be the same as the charge on the compound
d. it will be the same in the products is in the reactants
Answer is: a. it is determined from known oxidation state of an element within a compound determined.
Oxidation state (oxidation number) shows the degree of oxidation of an atom in a chemical compound.
For example, chlorate ion (ClO₃⁻) has negative charge.
One oxygen atom in this anion (negatively charged ion) has the oxidation number -2. There are three oxygen atoms in chlorate anion.
x + 3 · (-2) = -1.
x = -1 + 6.
x = +5; the oxidation number of chlorine.
The oxidation state of Cl (chlorine) in chlorate ion is +5.
Which statement is true about sodium hydroxide (NaOH)?
It is a salt because it increases the concentration of metallic ions.
It is a salt because it is formed by the reaction of an acid and a base.
It is a base because it increases the concentration of hydrogen ions.
It is a base because it increases the concentration of hydroxide ions.
The answer is; It is salt because it is formed by the reaction of an acid and a base.
Salt is composed of cations and anions (with a net charge of 0) joined together by ionic bonds attributed to their complementary charges. NaOH is an alkali salt because it forms an alkaline solution when dissolved in water – because it dissociates hydroxide ions.
Answer:
the answer is B for short
Explanation:
:)
when the equation N=O/P is solved for P correctly, the equation should read:
Given the equation N=O/P, solve for P by multiplying the left and right by P/N:
N * P/N = O/P * P/N
P = O/N
eqn N=O/P
solve for P
P=O/N
In an isolated system, two copper bars at different temperatures transfer energy until both are at the same temperature. How would the transfer of energy be different if the bars were in an open system?
A. Energy transfer would occur only between the copper bars.
B. Energy transfer would occur between the copper bars and the surroundings.
C. No energy transfer would occur between the copper bars or the surroundings.
D. Energy transfer would occur only with the surroundin
Answer is: B. Energy transfer would occur between the copper bars and the surroundings.
Closed system is a physical system that does not allow transfer of mass and energy in or out of the system.
Open system is a physical system that does allow transfer of mass and energy in or out of the system, have input and output flows.
Thermal conductuction is the transfer of heat through physical contact. Thermal conduction is the transfer of heat by microscopic collisions of particles.
Heat spontaneously flows from a hotter to a colder body.
Why does earth’s rotation axis lean toward the sun for only one-half of its orbit?
The earth is inclined to the plane of its orbit by 23.5 degrees. Therefore for half the time in its earth on its orbit, the north pole will be inclined towards the sun. During this period, the pole receives six months of continuous sunshine. In the other half of the revolution around the sun, the north pole is tilted away from the sun hence receives darkness for 6 months.
how can you tell a Cu(No3)2 solution from a Ni(NO3)2 solution?
Answer: [tex]Cu(NO_3)_2[/tex] solution has blue color and [tex]Ni(NO_3)_2[/tex] solution has bright green color.
Explanation:
[tex]Cu(NO_3)_2(aq)\rightarrow Cu^{2+}(aq)(blue)+ NO_{3}^{1-}(aq)[/tex]
[tex]Cu(NO_3)2[/tex] in its aqueous solution gives blue color solution. Copper being transition metal and gives characteristic color in their in aqueous solution.
[tex]Ni(NO_3)_2(aq)\rightarrow Ni^{2+}(aq)(green)+ NO_{3}^{1-}(aq)[/tex]
[tex]Ni(NO_3)2[/tex] in its aqueous solution gives bright green color solution. Nickel is also a transition metal and gives characteristic color in their in aqueous solution.
Cu(NO3)2 solution shows a deep blue color due to the Cu²⁺ ions it contains, whereas Ni(NO3)2 solution generally appears greenish due to the Ni²⁺ ions. You can distinguish these solutions by their colors.
Explanation:
You can distinguish between a Cu(NO3)2 (copper(II) nitrate) solution and a Ni(NO3)2 (nickel(II) nitrate) solution by color. Specifically, Cu(NO3)2 solutions are typically characterized by a deep blue color due to the Cu²⁺ ions it contains.
On the other hand, Ni(NO3)2 solutions generally appear greenish, owed to the characteristic color of Ni²⁺ ions. Figures 19.40 and 18.36 show this difference -- while the copper nitrate solution shows a deep blue color, a nickel nitrate solution would appear more greenish.
Thus, by observing the color of the solutions, it is possible to distinguish between them based on the characteristic color patterns of their constituent ions.
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balance chemical equation Fe3O4 = Fe + CO2
equation Fe3O4=Fe+CO2 is an impossible reaction
In a chemical equation, the arrow
A. can be read as "yields" or "makes."
B. always points toward the products.
C. separates the products and reactants.
D. all of these
In a chemical equation, the arrow
A. can be read as "yields" or "makes."
B. always points toward the products.
C. separates the products and reactants.
D. all of these
all of these options are right.
Answer: the answer is all of these
Explanation:
What is the primary difference between a hypothesis and a theory?
A theory is supported by more data and observations than a hypothesis is.
B hypothesis is falsifiable, but a theory has been proven to be correct.
C theory is a prediction, but a hypothesis is an explanation.
D hypothesis is more reliable than a theory.
The correct answer is B. hypothesis is falsifiable, but theory has been proven to be correct. A falsifiable thing is something that can be proved as false, also the hypothesis is an explanation that is suggested after an observation process. On the other hand, a theory is a more reliable source because it is verified, checked and proved after certain events that have evidence to certify.
PLEASE, I REALLY NEED HELP!!!!
Explain how metamorphic rocks are formed, and explain the difference between regional and contact metamorphism?
Why are the volcanoes on the Hawaiian islands northwest of the big island of Hawaii no longer erupting?
Use the terms RADIATION, CONDUCTION, and CONVECTION to explain how a pot of water boils?
Why is a minimum of three seismic stations needed to find the epicenter of an earthquake?
Answer all of them or just one, your choice!! :)
1. The metamorphic rocks are produced when the parent or the pre-existing rocks (whether sedimentary, igneous, or even metamorphic) are changed by pressure, heat, and the chemical activity of the fluids.
When the prime changing factor is heat, generally due to direct contact, it may go through fundamental modification in recrystallization and texture is known as contact metamorphism. While regional metamorphism takes place when the minerals and texture of the rock are modified by pressure and heat.
Metamorphic rocks form when heat and pressure transform existing rocks through contact or regional metamorphism. The volcanoes northwest of the Big Island of Hawaii are no longer erupting because they have moved away from the hotspot. To locate an earthquake's epicenter, data from a minimum of three seismic stations is required.
1). Metamorphic rocks are formed when existing rocks are transformed by heat and pressure. This process can occur through two main types of metamorphism: contact metamorphism and regional metamorphism.
Contact Metamorphism: Contact metamorphism happens when rocks are heated by nearby magma. The heat causes the minerals in the rocks to recrystallize without melting, creating new minerals and textures.Regional Metamorphism: Regional metamorphism occurs over large areas under high pressure and temperature conditions, typically associated with mountain-building processes at convergent plate boundaries. This type of metamorphism affects larger volumes of rock and often results in foliated textures.2). Volcanoes on Hawaiian Islands:
The volcanoes on the Hawaiian islands northwest of the Big Island of Hawaii are no longer erupting because they have moved away from the hotspot in the Earth's mantle that supplies magma. As the Pacific Plate moves northwestward, the older volcanoes are carried away from the hotspot, becoming dormant.
3). Boiling Water:
When explaining how a pot of water boils, three terms are essential: radiation, conduction, and convection.
Radiation is the heat transfer from the stove to the pot. Conduction is the direct heating of water molecules at the bottom of the pot. Convection occurs when the heated water rises and cooler water sinks, creating a circulating motion that leads to boiling.4). Finding Earthquake Epicenter:
A minimum of three seismic stations is needed to find the epicenter of an earthquake due to the process called triangulation. Each station records the time it takes for seismic waves to reach them, and by plotting circles with the quake's arrival time at each station, the intersection point of the three circles pinpoints the epicenter.
What would be the change in pressure in a sealed 10.0 l vessel due to the formation of n2 gas when the ammonium nitrite in 2.40 l of 0.900 m nh4no2 decomposes at 25.0°c?
The change in pressure in a sealed 10.0L vessel is 5.28 atm
calculation
The pressure is calculated using the ideal gas equation
That is P=n RT
where;
P (pressure)= ?
v( volume) = 10.0 L
n( number of moles) which is calculated as below
write the equation for decomposition of NH₄NO₂
NH₄NO₂ → N₂ +2H₂O
Find the moles of NH₄NO₂
moles = molarity x volume in liters
= 2.40 l x 0.900 M =2.16 moles
Use the mole ratio to determine the moles of N₂
that is from equation above NH₄NO₂:N₂ is 1:1 therefore the moles of N₂ is also =2.16 moles
R(gas constant) =0.0821 l.atm/mol.K
T(temperature) = 25° c into kelvin = 25 +273 =298 K
make p the subject of the formula by diving both side by V
P = nRT/V
p ={ (2.16 moles x 0.0821 L.atm/mol.K x 298 K) /10.0 L} = 5.28 atm.
Answer : The pressure of the gas will be, 5.285 atm
Solution : Given,
Volume of [tex]N_2[/tex] gas = 10 L
Temperature of gas = [tex]25^oC=273+25=298K[/tex] [tex](0^oC=273K)[/tex]
Volume of [tex]NH_4NO_2[/tex] = 2.40 L
Molarity of the ammonium nitrate solution = 0.9 M
First we have to calculate the moles of ammonium nitrate.
[tex]\text{ Moles of }NH_4NO_2=\text{ Molarity of }NH_4NO_2\times \text{ Volume of }NH_4NO_2[/tex]
[tex]\text{ Moles of }NH_4NO_2=(0.9mole/L)\times (2.40L)=2.16moles[/tex]
The balanced chemical reaction is,
[tex]NH_4NO_2\rightarrow N_2+2H_2O[/tex]
From the balanced reaction, we conclude that
1 mole of [tex]NH_4NO_2[/tex] decomposes to give 1 mole of [tex]N_2[/tex] gas
2.16 moles of [tex]NH_4NO_2[/tex] decomposes to give 2.16 moles of [tex]N_2[/tex] gas
Now we have to calculate the pressure of the gas.
using ideal gas equation,
[tex]PV=nRT[/tex]
where,
P = pressure of the gas
V = volume of the gas
T= temperature of the gas
n = number of moles of gas
R = gas constant = 0.0821 Latm/moleK
Now put all the given values in ideal gas equation, we get pressure of the gas.
[tex]P=\frac{nRT}{V}=\frac{(2.16mole)\times (0.0821Latm/moleK)\times (298K)}{10L}=5.285atm[/tex]
Therefore, the pressure of the gas will be, 5.285 atm
Given that the vapor pressure of water is 17.54 torr at 20 °c, calculate the vapor-pressure lowering of aqueous solutions that are 2.10 m in (a) sucrose, c12h22o11, and (b) sodium chloride. assume 100% dissociation for electrolytes.
Answer:
0.640 Torr; 1.28 Torr
Step-by-step explanation:
According to Raoult's Law,
(1) p₁ = χ₁p₁°,
where p₁ is the solvent
χ₁ + χ₂ = 1 Subtract χ₁ from each side
χ₂ = 1 – k₁ Substitute in (1)
(2) p₁ = (1 – χ₂)p₁° Remove parentheses
p₁ = p₁°- χ₂p₁° Subtract p₁° from each side
p₁ - p₁° = -χ₂p₁° Multiply each side by -1
Δp = χ₂p₁°
Δp is the vapour pressure lowering.
If the solute is an electrolyte, we must insert the van't Hoff i factor.
ΔP = iχ₂P₁°
===============
(1) Calculate χ₂ for each solution
Water:
1000 g = 1000 × 1/18.02
= 55.49 mol
χ₂ = 2.10/(2.10 + 55.49)
= 2.10/57.59
= 0.036 46
===============
(2) Calculate the vapour pressure lowering
(a) Sucrose
i = 1
ΔP = 1 × 0.036 46 × 17.54
ΔP = 0.640 Torr
=====
(b) NaCl
i = 2
ΔP = 2 × 0.640
ΔP = 1.28 torr
A natural gas stove transforms R energy into P energy. What do R and P most likely represent?
A. R represents chemical energy, P represents thermal energy
B. R represents thermal energy, P represents chemical energy
C. R represents potential energy, K represents electrical energy
D. R represents electrical energy, K represents potential energy
Answer:
A. R represents chemical energy; P represents thermal energy.
Step-by-step explanation:
The molecules in the gas contain chemical energy (R).
When the gas burns, the chemical energy is released as heat, or thermal energy (P).
Answer:
A. R represents chemical energy; P represents thermal energy.
Explanation:
in the late 1 800s , experiments using cathode ray tubes led to the discovery of the
In the late 1800's, experiments using cathode ray tubes led to the discovery of the;
Electron(s)
It was founded that many different metals release cathode rays, and that cathode rays were made of electrons, very small negatively charged particles.
Which of the following rock types form from placing other rocks under heat and pressure? A. Sedimentary rock B. Metamorphic rock C. Intrusive igneous rock D. Extrusive igneous roc
Your answer should be metamorphic rock.
I think the answer is B. Metamorphic rock.
An element consists of two isotopes. One with a mass of 79.95 amu and an abundance of 29.9%. The second isotope has a mass of 81.95 amu with an abundance of 70.1%. What is the molar mass of this element?
the molar mass of the element is 81.36 g/mol
calculation
step 1 : multiply each %abundance of the isotope by its mass number
that is 79.95 x 29.9 =2391
81.95 x 70.1 = 5745
Step 2: add them together
2390.5 + 5744.7 =8136
Step 3: divide by 100
= 8136/100 = 81.36 g/mol
Wine goes bad soon after opening because the ethanol ch3ch2oh in it reacts with oxygen gas o2 from the air to form water h2o and acetic acid ch3cooh , the main ingredient of vinegar. what mass of acetic acid is produced by the reaction of 7.0g of oxygen gas?
Answer:
4.3 g
Explanation:
We know we will need a balanced equation with masses and molar masses, so let’s gather all the information in one place.
M_r: 60.05 32.00
CH₃CH₂OH + 3O₂ ⟶ 2CO₂ + 3H₂O
Mass/g: 7.0
1. Calculate the moles of O₂
Moles O₂ = 7.0 × 1/32.00
Moles O₂ = 0.219 mol O₂
=====
2. Calculate the moles of CH₃CH₂OH
The molar ratio is 1 mol CH₃CH₂OH:3 mol O₂
Moles of CH₃CH₂OH = 0.219 × 1/3
Moles of CH₃CH₂OH = 0.0729 mol CH₃CH₂OH
======
3. Calculate the mass of CH₃CH₂OH
Mass of CH₃CH₂OH = 0.0729 × 60.05
Mass of CH₃CH₂OH = 4.4 g
In a mixture of argon and hydrogen, occupying a volume of 1.18 l at 894.6 mmhg and 44.1oc, it is found that the total mass of the sample is 1.25 g. what is the partial pressure of argon?
To solve the question, there is a need to use the equation:
PV = nRT
(894.6/760) × 1.18 = n × 0.0821 × (273 + 44.1)
By solving we get:
Total moles, n = 0.053
Assume, the moles of argon as a and of hydrogen as b,
So,
40 × a + 2 × b = 1.25 --------- (i)
a + b = 0.053 ------- (ii)
By solving i and ii we get:
a = 0.03,
Thus, mole fraction of Ar = XAr = 0.03/0.053 = 0.57
So,
Partial pressure of Ar = 894.6 × XAr = 894.6 × 0.57 = 509.92 mm Hg
Gastric acid pH can range from 1 to 4, and most of the acid is HCl.
For a sample of stomach acid that is 3.03x10^-2 M in HCl, how many moles of HCl are in 10.9 mL of the stomach acid?
The amount of HCl in a solution can be calculated by multiplying the solution's volume by its molarity. In the context of gastric acid with a molarity of 3.03x10^-2 M, there are approximately 3.3x10^-4 moles of HCl in 10.9 mL of the solution.
Explanation:The concentration of a solution is typically expressed in moles per liter (M), which denotes the amount of substance (in moles) present in one liter of the solution. When dealing with hydrochloric acid (HCl) in the context of gastric acid, a solution's molarity can be used to calculate the amount of HCl in a specific volume of the solution.
Given that the concentration of HCl in the gastric acid is 3.03x10^-2 M, there are 3.03x10^-2 moles of HCl in one liter of the solution. We are interested in finding out how many moles of HCl are present in 10.9 mL (or 0.0109 L) of the solution. This can be done by multiplying the volume of the solution by its molarity:
Moles of HCl = Volume in L x Molarity
Moles of HCl = 0.0109 L x 3.03x10^-2 M
So, the quantity of HCl in 10.9 mL of gastric acid is approximately 3.3x10^-4 moles.
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The number of moles of HCl in 10.9 mL of stomach acid that is 3.03x10^-2 M can be calculated using the concentration and volume. The result is 3.32x10^-4 moles of HCl.
Explanation:The stomach acid is primarily composed of HCl and has a pH range of 1 to 4. To determine the number of moles of HCl in 10.9 mL of stomach acid that is 3.03x10^-2 M in HCl, we can use the formula:
Moles of solute (HCl) = concentration (M) x volume (L)
Converting the volume of stomach acid from mL to L (10.9 mL = 0.0109 L) and substituting the given values into the formula:
Moles of HCl = 3.03x10^-2 M x 0.0109 L = 3.32x10^-4 moles
Therefore, there are 3.32x10^-4 moles of HCl in 10.9 mL of the stomach acid.
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which pattern is a characteristic of a graph of exponential growth A straight line B rises sharply on the right C A shape D rises sharply on the left
B rises sharply on the right
The pattern which serves as a characteristic of a graph of exponential growth is that it B rises sharply on the right .
What is an Exponential growth?Exponential growth serves as a consistent growth rate that brings about rapid increase in growth as total growth numbers increase.
It do takes place when there is an instantaneous rate of change of a quantity with respect to time.
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A chemist takes 50-gram sample of sulfur powder that has a melting point of 115.2 °C. What is the melting point of a 100-gram sample of sulfur powder?
115.2 °C since melting point is an extensive property
115.2 °C since melting point is an intensive property
Double of 115.2 °C since melting point is an intensive property
Double of 115.2 °C since temperature is an extensive property
Answer:
115.2 °C since melting point is an intensive property
Step-by-step explanation:
The melting point of a substance does not depend on how much you have.
For example, the melting point of water is 0 °C, whether it is an ice cube from the refrigerator or in the frozen pond outside.
The freezing point of a substance is an intensive property.
Thus, the melting point of 100 g of sulfur is 115.2 °C because melting point in an intensive property.