Caffeine, a stimulant found in coffee and soda, has the following elemental composition: 49.48% carbon, 5.19% hydrogen, 16.48% oxygen and 28.85% nitrogen. The molar mass of caffeine is 119.19 g/mol. Determine the molecular formula of caffeine.

Answers

Answer 1

Answer:

Explanation:

C = 49.48

H = 5.19

O = 16.48

N = 28.85

ratio of moles

= 49.48 / 12 : 5.19 / 1 : 16.48 / 16 : 28.85 / 14

= 4.123 : 5.19 : 1.03 : 2.06

= 4 : 5 : 1 : 2

so the empirical formula = C₄ H₅O N₂

Let molecular formula = (  C₄ H₅ON₂ )ₙ ,

n ( 48 + 5 + 16 + 28 ) = 119.19

97 n = 194.19

n = 2 ( approx )

molecular formula = C₈ H₁₀O₂ N₄


Related Questions

If 49.0 g of O2 is mixed with 49.0 g of H2 and the mixture is ignited, what is the maximum mass of water that may be produced?

Answers

Answer:

[tex]55.2gH_2O[/tex]

Explanation:

Hello!

In this case, since the reaction between hydrogen and oxygen to produce water is:

[tex]2H_2+O_2\rightarrow 2H_2O[/tex]

When equal masses of each reactant go in contact to carry out the reaction, we can identify the maximum mass of yielded water as the fewest mass yielded by each reactant, just as shown below:

[tex]m_{water}^{by\ H_2}=49.0gH_2*\frac{1molH_2}{2.02gH_2}*\frac{2molH_2O}{2molH_2}*\frac{18.02gH_2O}{1molH_2O} =170gH_2O\\\\m_{water}^{by\ O_2}=49.0gO_2*\frac{1molO_2}{32.0gO_2}*\frac{2molH_2O}{1molO_2}*\frac{18.02gH_2O}{1molH_2O} =55.2gH_2O[/tex]

Thus, since hydrogen yields more water than real, we limit the maximum mass of water to those 55.2 g yielded by oxygen as hydrogen would be in excess.

Best regards!

For a 0.300 mol sample of helium gas in a 0.200 L container at 248K, will the pressure be greater if calculated with the ideal gas law or the van der Waals equation, and by roughly how much? (For He,a=0.0342L2atmmol2,b=0.0237 Lmol)

Answers

Answer:

It changes by roughly 1 atm.

Explanation:

Hello!

In this case, since the ideal gas equation differs from the van der Waals' one by the presence of the a and b parameters which correct the assumption of no interactions into the container, they are written as:

[tex]P=\frac{nRT}{V}\\\\P=\frac{RT}{v_m-b}-\frac{a}{v_m^2}[/tex]

Thus, the pressure via the ideal gas equation is:

[tex]P=\frac{0.300mol*0.082\frac{atm*L}{mol*K}*248K}{0.200L}=30.5atm[/tex]

And the pressure via the van der Waals equation, considering the molar volume (vm=0.200L/0.300L=0.667L/mol) is:

[tex]P=\frac{0.082\frac{atm*L}{mol*K}*248K}{0.667L/mol-0.0237L/mol}-\frac{0.0342atm*L^2/mol^2}{(0.667L/mol)^2}\\\\P=31.6atm-0.0769atm\\\\P=31.5atm[/tex]

It means that the pressure change by 1 atm, which is not a significant difference for helium.

The difference in pressure calculated by the two methods is 84 atm.

The ideal gas equation is given by

PV =nRT

From the data given in the question;

P = ?

V = 0.200 L

n =  0.300 mol

T = 248K

R = 0.082 atmLK-1Mol-1

P = nRT/V

P =  0.300 mol × 0.082 atmLK-1Mol-1  × 248K/0.200 L

P = 30.5 atm

From Van der Waals equation;

P = RT/V - b - a/V^2

P =  (0.082 × 248/0.200 - 0.0237)  - (0.0342/ 0.200^2)

P = 114.5 atm

The difference in pressure calculated by the two methods is;

114.5 atm -  30.5 atm = 84 atm

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According to the following reaction, how many moles of hydrobromic acid are necessary to form 0.274 moles bromine?
hydrobromic acid (aq) —>hydrogen (g) + bromine (1)
moles hydrobromic acid

Answers

Answer:

0.548 moles of HBr are required

Explanation:

Given data:

Number of moles of  hydrobromic acid = ?

Moles of bromine formed = 0.274 mol

Solution:

Chemical equation:

2HBr     →   H₂  + Br₂

Now we will compare the moles of HBr with Br₂.

               Br₂           :           HBr

               1               :            2

               0.274       :           2×0.274=0.548

Thus, 0.548 moles of HBr are required.

describe, in terms of the motion of particles in an object, how heat conduction transfers energy between objects or from one part of an object to another part at a lower temperature.

Answers

Answer:

Molecular movement

Explanation:

When an object gets hotter, its molecules gain more kinetic energy and then move faster. Therefore, the fast-moving molecules will cause those around them to move faster as well, and the colder (or more slow-moving molecule object) object or part is heated up.

PLS GIVE BRAINLIEST

Consider a monoprotic weak acid ( HAHA ) that is titrated with a strong base. What is the relationship between the strength of the weak acid and the pH of the solution at the equivalence point?A. There is no relationship between the strength of the acid and the pH at the equivalence point. B. The pH at the equivalence point is always 7 in an acid base titration. C. The weaker the acid, the higher the pH at the equivalence point. D. The stronger the acid, the higher the pH at the equivalence point.

Answers

Answer:

C. The weaker the acid, the higher the pH at the equivalence point.

Explanation:

In a titration, a solution which concentration is known is added gradually to another solution of unknown concentration, until the chemical reaction between the two solutions is complete.

The pH in the equivalence point is equal to 7.00 only if both the acid and base are strong. When one or both reactants are weak, the pH in the equivalence point is not equal to 7.00.

In the equivalence point, the amount of strong base (like NaOH) added is just enough to react stoichiometrically with the weak acid. The resulting solution "only" contains the conjugated base A⁻. A solution of Na⁺A⁻ is the solution of a weak base:

A⁻ + H₂O ⇄ HA + OH⁻              Kb=Kw/Ka

In the equivalence point of the titration of a weak base with a strong base, the pH is higher than 7.00 because at this point the acid is transformed into its conjugate base.

How many micrograms of sodium chloride (to 2 decimal places) can be added to 527 mL of 0.00150 M silver nitrate before a precipitate forms? (Ksp = 1.80 x 10-10)

Answers

Answer:

use google

Explanation:

An Sulfur tetrafluoride gas is collected at 23.0 °C in an evacuated flask with a measured volume of 20.0 L. When all the gas has been collected, the pressure in the flask is measured to be 0.230 atm . Calculate the mass and number of moles of sulfur tetrafluoride gas that were collected. Be sure your answer has the correct number of significant digits. mass: 1 g N10 mole: mol X & ? Explanation Check​

Answers

mass = 20.48 g

moles=0.1895

Further explanation

In general, the gas equation can be written  

Pv=nRT  

where  

P = pressure, atm  

V = volume, liter  

n = number of moles  

R = gas constant = 0.08205 L.atm / mol K  

T = temperature, Kelvin  

P=0.23 atm

V=20 L

T=23+273=296 K

[tex]\tt n=\dfrac{PV}{RT}=\dfrac{0.23\times 20}{0.082\times 296}=0.1895[/tex]

mass SF₄ (MW=108,07 g/mol) :

[tex]\tt 0.1895\times 108,07 g/mol=20.48~g[/tex]

How many milliliters of a 0.266 M CsNO3 solution are required to make 150.0 mL of 0.075 M CsNO3 solution

Answers

Answer:

The required milliliters of CsNO3 in solution 1 = 42.29 mL

Explanation:

Given that:

The molarity of CsNO3 in solution 1 M₁= 0.266 M

The Volume of CsNO3 in solution 1 V₁  =   ???

The Volume of CsNO3 in solution 2 V₂ = 150.0 mL

The molarity of CsNO3 in solution 2 M₂= 0.075 M

By the application of the titrimetric concept:

M₁V₁ = M₂V₂

We have;

0.266 M ×  V₁  = 0.075 M × 150.0 mL

V₁  = ( 0.075 M × 150.0 mL ) / 0.266 M

V₁  = (11.25 / 0.266 ) mL

V₁  = 42.29 mL

When water boils, it pushes upward against the air pressure pushing down on it. If there is less air pressure, how does that affect the pooling point ?

Answers

It’s affects it because it basically pushes up the water pressure from h2o to h3o

Helium is a....

a. metalloid
b. nonmetal
c. metal

Answers

B be ace it’s not mealy

Answer:

Nonmetal

Explanation:

Electric charges that are different attract each other.
True
False

Answers

Answer:

it is true bc i looked it up

Electric charges that are different attract each other.
True
False

Answer: True

What is the temperature 0 Kelvin called?

What happens at that temperature?

Answers

Answer:

0 Kelvin is called Absolute Zero. Particles will stop moving, and lose all energy.

What elements make up water?

Answers

Water molecules are made of hydrogen atoms and one oxygen atom.

Hope this helped!

Answer:

1 oxygen and 2 hydrogen

Assume that the top of your head has a surface area of 25 cm x 25 cm. How many newtons of force push on your head at sea level? If you estimate this area to be 100 in2, what is the force in pounds?

Answers

Answer:

(a) 6332.812 N (b) 1469.59  pounds.

Explanation:

Given that,

The surface area of the top of yu head is 25 cm x 25 cm

Area = 625 cm² = 0.0625 m²

Atmospheric pressure on it is 101325 Pa.

(a) Pressure acting on an object is given by force acting per unit area. It can be written as :

[tex]P=\dfrac{F}{A}\\\\F=PA\\\\F=101325\ Pa\times 0.0625\ m^2\\\\F=6332.812\ N[/tex]

6332.812 N of force is acting on your head at sea level.

(b) If area, A = 100 in²

We know that,

1 atm = 14.6959 pounds/in²

[tex]P=\dfrac{F}{A}\\\\F=PA\\\\F=14.6959 \ \text{Pounds}/in^2\times 100\ in^2\\\\F=1469.59\ \text{pounds}[/tex]

So, the force is 1469.59  pounds.

A. The force required to push your head at sea level is 6332.8125 N

B. The force in pound is 1469.59 lb

A. Determination of the force required at sea level.

Pressure (P) = 101325 Nm²

Area (A) = 25 cm × 25 cm = 0.25 m × 0.25 m = 0.0625 m²

Force (F) =?

P = F / A

Cross multiply

F = PA

F = 101325 × 0.0625

F = 6332.8125 N

Therefore, the force required to push your head at sea level is 6332.8125 N

B. Determination of the force in pounds

Area (A) = 100 in²

Pressure (P) = 14.6959 pound / in²

Force (F) =?

F = PA

F = 14.6959 × 100

F = 1469.59 lb

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A buffer solution is made that is 0.347 M in H2C2O4 and 0.347 M KHC2O4.

1. If Ka for H2C2O4 is 5.90E^-2, what is the pH of the buffer solution?
b. Write the net ionic equation for the reaction that occurs when 0.070 mol KOH is added to 1.00 L of the buffer solution.

Answers

Answer:

1. pH = 1.23.

2. [tex]H_2C_2O_4(aq) +OH^-(aq)\rightarrow HC_2O_4^-(aq)+H_2O(l)[/tex]

Explanation:

Hello!

1. In this case, for the ionization of H2C2O4, we can write:

[tex]H_2C_2O_4\rightleftharpoons HC_2O_4^-+H^+[/tex]

It means, that if it is forming a buffer solution with its conjugate base in the form of KHC2O4, we can compute the pH based on the Henderson-Hasselbach equation:

[tex]pH=pKa+log(\frac{[base]}{[acid]} )[/tex]

Whereas the pKa is:

[tex]pKa=-log(Ka)=-log(5.90x10^{-2})=1.23[/tex]

The concentration of the base is 0.347 M and the concentration of the acid is 0.347 M as well, as seen on the statement; thus, the pH is:

[tex]pH=1.23+log(\frac{0.347M}{0.347M} )\\\\pH=1.23+0\\\\pH=1.23[/tex]

2. Now, since the addition of KOH directly consumes 0.070 moles of acid, we can compute the remaining moles as follows:

[tex]n_{acid}=0.347mol/L*1.00L=0.347mol\\\\n_{acid}^{remaining}=0.347mol-0.070mol=0.277mol[/tex]

It means that the acid remains in excess yet more base is yielded due to the effect of the OH ions provided by the KOH; therefore, the undergone chemical reaction is:

[tex]H_2C_2O_4(aq) +OH^-(aq)\rightarrow HC_2O_4^-(aq)+H_2O(l)[/tex]

Which is also shown in net ionic notation.

Best regards!

A chemist prepares a solution of copper(II) sulfate by measuring out 17.2 of copper(II) sulfate into a volumetric flask and filling the flask to the mark with water. Calculate the concentration in of the chemist's copper(II) sulfate solution.

Answers

Answer:

Concentration of the chemist's copper(II) sulfate solution is 0.43 mol/L

Note: The volume of the flask is assumed  to be 250 mL

Explanation:

Since the volume of the volumetric flask is not given, we assume the volume its volume to be 250 mL.

Mass of copper (ii) sulfate = 17.2 g; molar mass of copper (ii) sulfate = 160 g/mol

Concentration in mol/L = number of moles/volume in litres

Number of moles of copper (ii) sulfate = 17.2 g / 160 g/mol = 0.1075 moles

Volume of flask in litres = 250 mL/1000 mL * 1 L = 0.250 L

Concentration = 0.1075 moles / 0.250 L = 0.43 mol/L

Therefore, concentration of the chemist's copper(II) sulfate solution is 0.43 mol/L

Answer:

0.5000

Explanation:

We can measure the concentration of the copper sulfate solution as 1.000 mol/L. Since the tank contains one half liter, the solution contains 0.5000 moles of copper sulfate.

The sample of 15.0 g of KCl is dissolved into a solution with a total volume of 250.0 mL. What is the molarity of KCl in the solution?

Answers

Answer:

0.805 M.

Explanation:

Hello!

In this case, since the molarity of a solution is computing by dividing the moles of solute over the volume of solution in liters (M=n/V), for 15.0 g of potassium chloride (74.55 g/mol) we compute the corresponding moles:

[tex]n=15.0gKCl*\frac{1molKCl}{74.55gKCl}=0.201molKCl[/tex]

Next, since the volume is 0.2500 in liters, the molarity turns out:

[tex]M=\frac{0.201mol}{0.2500L} \\\\M=0.805M[/tex]

Best regards!

Sealed containers of fizzy drinks contain dissolved carbon dioxide. The dissolved CO2 is in equilibrium with a small quantity of gaseous CO2 at the top of the container.

Find partial pressure of CO2 gas in 355 ml can of fizzy drink at 25C if the concentration of CO2 in the fizzy drink 0.1 M. Given that Henry’s law constant for CO2 is 3.3 x 10-2 M atm-1.

What mass of CO2 is dissolved in a 355 ml can of fizzy drink when it is stored at 25C.

Answers

Answer:

3 atm

1.6 g

Explanation:

Step 1: Given data

Volume of the solution (V): 355 mLConcentration of the solution (C): 0.1 MHenry’s law constant for CO₂ (k): 3.3 × 10⁻² M atm⁻¹.

Step 2: Find partial pressure (P) of CO₂ gas

We will use Henry's law.

C = k × P

P = C / k

P = 0.1 M / 3.3 × 10⁻² M atm⁻¹

P = 3 atm

Step 3: Calculate the mass of CO₂ gas

The molar mass of carbon dioxide is 44.01 g/mol.

0.355 L × 0.1 mol/L × 44.01 g/mol = 1.6 g

Name something that has zero thermal energy.

Answers

Absolute zero is the point at which the fundamental particles of nature have minimal vibrational motion, retaining only quantum mechanical, zero-point energy-induced particle motion.
Hope this helped! c:

Answer:

When all molecules in a system stop moving completely, there is zero thermal energy

Explanation:

It is impossible to reach though

The reaction between iron(II) oxide and carbon monoxide produces iron and carbon dioxide. How many moles of iron can be obtained when 1.50 mol FeO reacts with an excess of CO ?

FeO+CO⟶Fe+CO2

Answers

Answer:

1.5 moles of Fe produced.

Explanation:

Given data:

Moles of FeO react = 1.50 mol

Moles of iron produced = ?

Solution:

Chemical equation:

FeO + CO       →       Fe + CO₂

Now we will compare the moles of ironoxide with iron.

                           FeO          :           Fe

                              1             :             1

                             1.5           :           1.5

Thus from 1.5 moles of FeO 1.5 moles of Fe are produced.                                    

1.5 moles of Fe can be obtained when 1.50 mol of FeO reacts with an excess

of CO

Moles of FeO reacted  = 1.50 mol

Moles of iron produced = ? mol

The chemical equation is given as

FeO + CO       →       Fe + CO₂

Comparisons of FeO and Fe show they are in the ratio 1 : 1

                          FeO          :           Fe

                            1.5           :           1.5

which translates to the number of moles being equal

Therefore, 1.5 moles of FeO 1.5 moles of Fe are produced.    

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A car traveled 150 meters in 5 seconds, what was its speed? 1.
Pepper the dog traveled 100 meters in 10 seconds, what was Pepper’s speed? 2.
Tony drove his car 1000 meters in 2 minutes, what was the speed of the car? 3.
A bird is flying over New York at a speed of 10 miles per minute. It traveled at this speed for 20 minutes. How far did it fly? 4.



Answer Them all and get 25 points!!!!

Answers

Answer:

1.  car traveled 30 meters per second

2. pepper traveled 10 meters per second

3. tony drove around 500 meters per minute

4. the bird traveled 200 miles

Hope this helped!

1 .30
2.10
3.500
4.200

I need help, due in 30 mins

Answers

Answer:

1.Reaction rate is how fast a chemical reaction proceeds.

2.Nature of the reaction, Pressure factor

, Solvent, Catalyst and inhibitors.

3.Physical change is a temporary change. A chemical change is a permanent change. A Physical change affects only physical properties i.e. shape, size, etc.

4. One example of the effect of temperature is the use of lightsticks or glowsticks.

5.When the particle size of a fixed mass of a solid reactant becomes smaller, the total exposed surface area becomes larger, the rate of reaction increases. an example could be ice and water when the atoms are stuck together a solid but all over the place as a liquid.

6. Sometimes a reaction depends on catalysts to do their job. In that case, changing the concentration of the catalyst can speed up or slow down the reaction. For example, enzymes speed up biological reactions, and their concentration affects the rate of reaction.

7.A catalyst is a chemical substance that affects the rate of a chemical reaction by altering the activation energy required for the reaction to proceed. For example, a catalyst could cause a reaction between reactants to happen at a faster rate or at a lower temperature than would be possible without the catalyst.

Explanation:

I hope this helps have a great day! :)

Describe the relationship between predator and prey in a balanced ecosystem

Answers

Answer:

The predator-prey relationship helps to hold the populations of the two species in equilibrium. ... If the population of prey increases, there is more food for predators. So after a slight period, the predator population is also increasing. If the number of predators increases, more prey is captured.

Explanation:

Answer:

i eat you, you die

Explanation:

thats how life works

Look at the picture below. Name the isotope.

Answers

Answer:

carbon-13

Explanation:

For the following reaction at equilibrium SO3(g) + NO(g) = SO2(g) + NO2(g)It is found that [SO2] = 0.70 M and [NO] = 1.20 M. Calculate the equilibrium constant for the readction knowing that the initial concentration were [SO3] = 2.55 M and [NO] = 1.90 M.

Answers

Answer:

[tex]K=0.14[/tex]

Explanation:

Hello!

In this case, for the undergoing chemical reaction, we can write the equilibrium expression via:

[tex]K=\frac{[SO_2][NO_2]}{[SO_3][NO]}[/tex]

Whereas the equilibrium concentration of both SO3 and NO are 2.55 M and 1.90 M respectively, it means that the extent of reaction [tex]x[/tex] is:

[tex]x=1.90M-1.20M=0.7M[/tex]

Because the equilibrium expression in terms of the reaction extent is:

[tex]K=\frac{x*x}{([SO_3]_0-x)([NO]_0-x)}[/tex]

It means that the concentration of SO3, NO, SO2 and NO2 at equilibrium are:

[tex][SO_3]=2.55M-0.70M=1.85M[/tex]

[tex][NO]=1.20M[/tex]

[tex][SO_2]=0.70M[/tex]

[tex][NO_2]=0.70M[/tex]

Thus, the equilibrium constant for such reaction is:

[tex]K=\frac{0.70*0.70}{1.85*1.90}\\\\K=0.14[/tex]

Best regards!

i am a metal with electrons in 5 energy levels that can form ions with a +2 charge

Answers

Sr - Strongium. i believe lol

give an example of coupling reaction​

Answers

Answer:

An example is the formation of ATP, which is an endergonic process and is coupled to the dissipation of a proton gradient.

Explanation:

Hope this helped!

Help ASAP
Please and thank you

Answers

Answer: C

Explanation: Everything else is true.

The answer is c because it’s the only one that is not true

What is the atomic mass of aluminum?
Help ASAP!!!! Already got a D in that class subject is science but that’s the closed I can get

Answers

Answer:

26.982

Explanation:

Use the periodic table

Is iron man made or natural

Answers

Answer:

Iron is natural. Paper is man-made

Explanation:

Answer:

iron

Explanation:

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