1. The chemical formula of caffeine is C8H10N4O2. Determine the percent composition of the molecule.
Show work please

Answers

Answer 1

Answer:

we find the mass for each element in one mole by multiplying the number of atoms in one molecule with the atomic mass

mC=8Ac=8*12=96g

mH=10AH=10*1=10g

mN=4AN=4*14=56g

mO=2AO=2*16=32g

by adding the masses together we find the molar mass of the molecule

M=mC+nH+mN+mO=96+10+56+32=194g/mole

we apply the rule of threes to find the percentage of each element

194g..96gC..10gH...56gN....32gO

100g....a...........b...........c.............d

a=(100*96)/194=49.48%C

b=(100*10)/194=5.19%H

c=(100*56)/194=28.85%N

d=(100*32)/194=16.48%O

Explanation:


Related Questions

Separation units often use membranes, absorbers, and other devices to reduce the mole fraction of selected constituents in gaseous mixtures. Consider a mixture of hydrocarbons that consists of 62 percent (by volume) methane, 28 percent ethane, and 10 percent propane. After passing through a separator, the mole fraction of the propane is reduced to 1 percent. The mixture pressure before and after the separation is 100 kPa. Determine the change in the partial pressures of all the constituents in the mixture.

Answers

Answer:

See explanation

Explanation:

We first obtain the mole fraction of propane at the start and end;

0.01 = x/0.62 + 0.28 + x

0.01[0.62 + 0.28 + x] = x

0.01[0.9 + x] =x

9 * 10^-3 + 0.0.1x = x

9 * 10^-3 = x - 0.0.1x

9 * 10^-3 = 0.99x

x = 9 * 10^-3/0.99

x = 9.09 * 10^-3

After

For methane

0.62/ 0.28 + 0.62 + 9.09 * 10^-3     = 0.68

For ethane

0.28/0.28 + 0.62 + 9.09 * 10^-3       =0.31

Change in partial pressure of methane = (0.68 - 0.62) * 100kPa = 6 kPa

Change in partial pressure of ethane = (0.31 - 0.28) * 100kPa = 3 kPa

Change in partial pressure of propane= (0.01 - 0.1) * 100kPa = -9 kPa

At which position on the diagram would an apple have the greatest potential energy?

Answers

Answer:

Position 1 because it is the highest from the ground.

Hope this helps!

What is the correct illustration of the bonding that occurs in H2O?

Answers

Answer:

covalent is the bonding that occurs in H2O  

Explanation:

Select odd one out.
I) O
II) Na
III) Cu
IV) Ag

Answers

Explanation:

0 is the odd one...............

and rest are metals and they lose electron and 0 gain electron and is non metal

I) O , is the odd one out because Na, Cu , Ag are all metals while O is a nonmetal ( look from periodic table )

Suppose a fox population exists in an ecosystem. Some of the foxes maintain a heavy coat year-round, while others shed their heavy coat in the summer. Summers in this ecosystem
are becoming steadily hotter because of global warming. Which members of the species will most likely be able to adapt to the changing temperatures?

subject science

Answers

Answer:

The fox who shed their heavy coat in the summer.

Explanation:

If a fox has the ability to shed its coat in the summer, it will have no difficulties adapting to new temperatures even during winter. However, the heavy-coated one will.

When the equation H2 + Fe3O4 = Fe + H2O is completely balanced using the smallest whole numbers, the coefficient oH2 would be A.) 1 B.)2 C.) 3 D.) 4

Answers

Answer:

H2 would have a coefficient of 2.

Explanation:

According to the balanced chemical equation, the coefficient of hydrogen is 4.

What is chemical equation?

Chemical equation is a symbolic representation of a chemical reaction which is written in the form of symbols and chemical formulas.The reactants are present on the left hand side while the products are present on the right hand side.

A plus sign is present between reactants and products if they are more than one in any case and an arrow is present pointing towards the product side which indicates the direction of the reaction .There are coefficients present next to the chemical symbols and formulas .

The first chemical equation was put forth by Jean Beguin in 1615.By making use of chemical equations the direction of reaction ,state of reactants and products can be stated. In the chemical equations even the temperature to be maintained and catalyst can be mentioned.

Learn more about chemical equation,here:

https://brainly.com/question/28294176

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whoever can help me will get the brainliest! Please

Answers

Answer:

Food chain, in ecology, the sequence of transfers of matter and energy in the form of food from organism to organism. Food chains intertwine locally into a food web because most organisms consume more than one type of animal or plant. ... In a predator chain, a plant-eating animal is eaten by a flesh-eating animal.

Explanation:

The sound of a trumpet ECHOES off a nearby mountain. This is which type of wave interaction?

Answers

Answer:

reflection

Explanation:

wave reflection is when a sound bounces off something it cannot go through, like echoing

The job of the ______ is to hold all of the parts of a cell together

Answers

Answer:

cell membrane

Explanation:

it holds everything together

Pls help fast, I will give brainliest!

Answers

Answer:

c

Explanation:

Calculate the heat absorbed when 68.8 g of ice at -30.0 c is converted to steam at 160 c

Answers

Answer: 219 kJ

Explanation:

Methanol, CH3OH, is the simplest of the alcohols. It is synthesized by the reaction of hydrogen and carbon monoxide. Write chemical reactions. If 500 mol of CO and 750 mol of H2 are present, which is the limiting reactant?

Answers

Answer:

The limiting reactant is H₂

Explanation:

The reaction of hydrogen (H₂) and carbon monoxide (CO) to produce methanol (CH₃OH) is the following:

2H₂(g) + CO(g) → CH₃OH(g)

From the balanced chemical equation, we can see that 1 mol of CO reacts wIth 2 moles of H₂. So, the stoichiometric ratio is:

2 mol H₂/1 mol CO = 2.0

We have 500 mol of CO and 750 mol of H₂, so we calculate the ratio to establish a comparison:

750 mol H₂/500 mol CO = 1.5

Since 2.0 > 1.5, we have fewer moles of H₂ than are needed to completely react with 500 moles of CO. In fact, we need 1000 moles of H₂ and we have 750 moles. So, the limiting reactant is H₂.

Oday, you will observe drops of liquid water and compare them to drops of liquid isopropanol, noting whether either liquid evaporates. Given that the energy transferred in from the air will be the same for both liquids, make a prediction about whether both drops or only one drop will evaporate within five minutes. Explain your prediction below.

Answers

Answer:

Liquid isopropanol.

Explanation:

Liquid isopropanol will evaporate earlier than water because the boiling point of isopropanol is less than water. That liquid which have high boiling point require more heat energy for change into vapor state as compared to those liquids that has low boiling point. The isopropanol has boiling point i.e. 82.5 °C while on the other hand, water has boiling point i.e. 100 °C so we can say that isopropanol will evaporate first.

The liquid that will be the first to evaporate within 5 minutes is; Liquid Isopropanol

We have the 2 liquids as;

Liquid Isopropanol

Liquid water

Now, since we are dealing with the one that will evaporate within five minutes, we need to know their boiling points.

From online research;

Boiling point of liquid isopropanol is 82.5°C

Boiling point of liquid water is 100°C

Now, we are told that the same energy is transferred for both liquids. However, boiling point of the liquid with the lower boiling point will be achieved first and as a result will evaporate first since the next stage after boiling point is evaporation of steam.

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Does anyone know how kinetic energy and crater diameter are related??

Answers

Answer:

Crater size is related to the mass and velocity of the impacting body. Mass and velocity can be combined to find the kinetic energy of an impactor. ... This fundamental physical relationship allows an estimate of impactor mass to be made from crater diameter.

Explanation:

What does the prefix “geo” mean?
Please Help
I will give you Brainlist

Answers

derived from a greek word meaning “Earth” in most cases it means “global” or relate to the Earth somehow

I can determine the molar mass of an element by looking on the Answer under the atomic mass for the element.

Answers

Answer:

YES that is the molar mass can be found as the atomic mass of a single atom, BUT when you get to larger molecules your molar mass will be a combination of atomic masses.

Explanation:

In the Haber reaction shown below, _______?is the
limiting reactant if equal moles of each reactant are used.
3H2 + N2 -> 2NH3

Answers

Answer: hydrogen

Explanation:

how does pentene become pentane?
How does propene become propane?​

Answers

Pentane is derived from the petroleum raw materials, natural gas and crude oil. It is generally marketed in a compressed liquefied form at 99% purity.

Which of the following is a product in the reaction described by the word equation below?
iron + copper(II) sulfate ----------> iron(II) sulfate +copper

Answers

Answer:

Please answer my question

UGRENT! Please help showing all work

Answers

Answer:

a. Oxygen

b. 20.39g of Al₂O₃

c. 87%

Explanation:

In order to produce 2moles of Al₂O₃, we need to make react 4 moles of Al, to 3 moles of O₂.

We determine the limiting reactant with the moles of each:

12.98g / 26.98g/mol = 0.481 moles of Al

9.6g / 32g/mol = 0.300 moles of oxygen

4 moles of Al react to 3 moles of O₂

Then, 0.481 mol may react to (0.481 . 3)/4 = 0.361 moles

We only have 0.300 moles of O₂ and we need 0.361. Oxygen is the limiting reactant.

So 3 moles of O₂ can produce 2 moles of Al₂O₃

Our 0.300 moles may produce (0.300 . 2) / 3 = 0.200 mol

Our theoretical yield is: 0.2 mol . 101.96g/ mol = 20.39 g

To determine the percent yield we calculate:

(Produced yield/ Thoeretical yield) . 100 → (17.74 /20.39) . 100 = 87%

28g of aluminum reacts with 45g oxygen

1) complete balanced equation?
2) what is the limiting reactant?
3) how many grams of product could be formed?
4) how many grams of excess would you predict?
5) if you actually measured 50g of product, what is the percent yield?

Answers

Answer:

answer below:

Explanation:

1) 4 Al + 3 O2 --> 2Al2O3.

2) Al mol= 28/27 = 1.037mol

O mol= 45/16 = 2.812mol

Al : O

4 : 2

x : 2.812

cross multiply

4 x 2.812/2  = 5.624 mol of Al

Al is limiting reactant

3) 28/5.246 = 5.34product can be formed (not that much sure)

4) 45/ 0.5185 = 86.79

86.79 - 5.34 = 81.45g

5) 50 / 81.45 x 100 = 61.39% ( i guess)

i hope this hleps you

An organism from the past that is related to all the organisms in the group is called?​

Answers

Answer:

phylogenic trees/phylogeny

Explanation:

the evolutionary history and relationship of an organism or group of organisms is called its phylogeny

what is the molecular shape of N2O2?

Answers

Answer:

If you're just looking at the Lewis Structure from the perspective of the octet rule, it does appear that the structure is correct. Dinitrogen always has a lone pair of electrons which could conceivably be used for dative bonding as you suggest. So from that perspective there appears to be nothing wrong at all - other than that it doesn't exist in nature in this way.

Explanation:


2Na + 2H2O → 2NaOH+ H2
How many grams of sodium would be needed to produce 1.00kg of sodium hydroxide?

Answers

Answer:

575 g

Explanation:

1 kg of sodium hydroxide is 1000/40=25 mol.

So 25 mol of sodium will be needed.

25 mol of sodium is 575 g.

According to the stoichiometry of the given chemical equation, 575 g s of sodium would be needed to produce 1.00 kg of sodium hydroxide.

What is chemical equation?

Chemical equation is a symbolic representation of a chemical reaction which is written in the form of symbols and chemical formulas.The reactants are present on the left hand side while the products are present on the right hand side.

A plus sign is present between reactants and products if they are more than one in any case and an arrow is present pointing towards the product side which indicates the direction of the reaction .There are coefficients present next to the chemical symbols and formulas .

The first chemical equation was put forth by Jean Beguin in 1615.By making use of chemical equations the direction of reaction ,state of reactants and products can be stated. In the chemical equations even the temperature to be maintained and catalyst can be mentioned.

46 g sodium gives 80 g sodium hydroxide, thus 1000 g sodium hydroxide requires 46×1000/80=575 g sodium.

Thus, 575 g s of sodium would be needed to produce 1.00 kg of sodium hydroxide.

Learn more about chemical equation,here:

https://brainly.com/question/28294176

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What can the period number of an element tell us about that element?

Answers

Answer:

All of the elements in a period have the same number of atomic orbitals.

Explanation:

What are the layers of earth including the lithosphere and the asthenosphere?

Answers

Answer:

The lithosphere is the solid, outer part of the Earth. The lithosphere includes the brittle upper portion of the mantle and the crust, the outermost layers of Earth's structure. It is bounded by the atmosphere above and the asthenosphere (another part of the upper mantle) below

Explanation:

They are, in order from the exterior to the interior – the crust, the mantle, the outer core, and the inner core.

PLZ HELPP!!! WILL GIVE EXTRA POINTS AND BRAINLIEST!!! DUE IN 15 MINUTES!!!

As a scuba diving air tank is filled with air, the air is compressed in the tank to as much as 3000 psi of pressure. When filling the tank, it is observed that the tank becomes warmer.

Which argument BEST explains why this occurs?

A
When air is compressed, it turns solid. A short time later, the air evaporates back into a gas which releases heat.
B
When air is compressed, the molecules line up into a crystalline structure. As the molecules line up, they release energy in the form of heat.
C
When air is put into the tank, it expands rapidly, thereby raising the temperature.
D
Air molecules are free to move and as more air is added to the tank, the molecules move and collide faster which raises the temperature.

Answers

Answer:

The gas under pressure subjected to heat can cause the tank to explode. A scuba tank filled to capacity with compressed air at 3000 psi could just as easily go up to 3400-3500 psi if heated

Explanation:

Air molecules are free to move and as more air is added to the tank, the molecules move and collide faster which raises the temperature. Hence option D is correct.

What is pressure?

Pressure is defined as the force applied perpendicularly to an object's surface divided by the surface area over which it is applied. The movement of the molecules and the collisions they have with one another and the vessel walls cause the pressure to build up. According to general relativity theory, pressure contributes to the mass-energy cause of gravity by making a gravitational field stronger.

The tank may blow up if the gas within was under pressure and exposed to heat. If heated, the pressure of a scuba tank filled to capacity with compressed air at 3000 psi may readily increase to 3400-3500 psi. Because air molecules are free to move, the temperature in the tank rises as more air is introduced, as the molecules move and collide more quickly.

Thus, air molecules are free to move and as more air is added to the tank, the molecules move and collide faster which raises the temperature. Hence option D is correct.

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In a water molecule, what type of bond forms between the oxygen and hydrogen atoms

Answers

Covalent bond forms between the oxygen and hydrogen atoms.

(I attached a picture that could help)

-Hope that helps,
Good luck!

An intravenous solution of mannitol is used as a diuretic to increase the loss of sodium and chloride by a patient. If a patient receives 30.0 mL of 25% (m/v) mannitol solution, how many grams of mannitol were given?

Answers

Answer:

Explanation:

25 % ( m / v ) mannitol solution means 25 gram in 100 cc of water

25 gram in 100 mL of water

grams of mannitol in 30 mL = 25 x 30 / 100

= 7.5 grams .

What is the difference between a pure solvent and a solution? Do they have the same physical properties?

Answers

Answer:

The physical properties of a solution are different from those of the pure solvent. ... Colligative properties are those physical properties of solutions of nonvolatile solutes that depend only on the number of particles present in a given amount of solution, not on the nature of those particles.

Pure solvent v/s Solution:A solution is a homogeneous mixture consisting of a solute dissolved into a solvent while the solvent is the dissolving medium.The physical properties for both differs. Colligative properties are those physical properties of solutions of nonvolatile solutes that depend only on the number of particles present in a given amount of solution, not on the nature of those particles.Pure solvents have only one component like n-hexane, water while a solution is a mixture of solute and solvent for example: salt solution.The boiling point of the solvent in a solution is higher than that of the pure solvent.

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