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4 years ago

Help me please i don’t understand the problem

Chemistry

2 answers:

brilliants [131]4 years ago

5 0

Answer:

Atoms are neither created or destroyed.

Explanation:

The end result of a chemical change does not create or destroy any atoms. Matter cannot be created or destroyed, meaning the same amount of atoms exist before and after the change.

slega [8]4 years ago

5 0

A. Atoms are neither created nor destroyed

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A mixture containing nitrogen and hydrogen weighs 3.48 g and occupies a volume of 7.47 L at 296 K and 1.02 atm. Calculate the ma

Sonbull [250]

Answer:

there is 2% of hydrogen and 98% of nitrogen (mass percent)

Explanation:

assuming ideal gas behaviour

P*V=n*R*T

n= P*V/(R*T)

where P= pressure=1.02 atm , V=volume=7.47 L , T=absolute temperature= 296 K and R= ideal gas constant = 0.082 atm*L/(mole*K)

thus

n= P*V/(R*T) = 1.02 atm*7.47 L/( 296 K * 0.082 atm*L/(mole*K)) = 0.314 moles

since the number of moles is related with the mass m through the molecular weight M

n=m/M

thus denoting 1 as hydrogen and 2 as nitrogen

m₁+m₂ = mt (total mass)

m₁/M₁+m₂/M₂ = n

dividing one equation by the other and denoting mass fraction w₁= m₁/mt , w₂= m₂/mt , w₂= 1- w₁

w₁/M₁+w₂/M₂ = n/mt

w₁/M₁+(1-w₁) /M₂ = n/mt

w₁*(1/M₁- 1/M₂) + 1/M₂ = n/mt

w₁= (n/mt- 1/M₂) /(1/M₁- 1/M₂)

replacing values

w₁= (n/mt- 1/M₂) /(1/M₁- 1/M₂) = (0.314 moles/3.48 g - 1/(14 g/mole)) /(1/(1 g/mole)-1/(14 g/mole))= 0.02 (%)

and w₂= 1-w₁= 0.98 (98%)

thus there is 2% of hydrogen and 98% of nitrogen

4 0

3 years ago

Carbon disulfide burns in oxygen to yield carbon dioxide and sulfur dioxide according to the following chemical equation. CS2(l)

Semmy [17]

Answer:

a) the limiting reactant is 02

b) There will remain 0.667 moles of CS2

c) There will be formed 0.333 moles oof CO2 and 0.667 moles of SO2

Explanation:

Step 1: Data given

Number of moles of CS2 = 1.00 mol

Number of moles of O2 = 1.00 mol

Molar mass of O2 = 32 g/mol

Molar mass of CS2 = 76.14 g/mol

Step 2: The balanced equation

CS2(l) + 3O2(g) → CO2(g) + 2SO2(g)

Step 3: Calculate the limiting reactant

For 1 mole of CS2 we need 3 moles of O2 to produce 1 mol of CO2 and 2 moles of SO2

O2 is the limiting reactant. It will completely be consumed.(1.00 mol).

CS2 is in excess. There will react 1.00/ 3 = 0.333 moles

There will remain 1.00 - 0.333 = 0.667 moles of CS2

Step 4: Calculate moles of CO2 and SO2

For 1 mole of CS2 we need 3 moles of O2 to produce 1 mol of CO2 and 2 moles of SO2

For 1.00 mol of O2 we have 1.00/3 = 0.333 moles CO2

For 1.00 mol of O2 we have 1.00 /(3/2) = 0.667 moles of SO2

8 0

3 years ago

Did i answer these right??

WITCHER [35]

All of them are right except the neutron one. The neutrons is actually 176 because you subtract the number of protons from the atomic mass to find this.

3 0

3 years ago

How many fluorine atoms bond with calcium to form calcium fluoride?

allsm [11]

2 atoms will bond with calcium to form Calcium Fluoride

3 0

3 years ago

Calculate the mass percent of ba(no3)2 in this solution, assuming the density of the solution is 1.000 kg/l.

viktelen [127]

You forgot to include the known characteristics of the solution.

I searched them and copy here:

volume: 1.000 liter

M = 0.0190 M

Now, you can start with the definition of mass percent.

mass percent = (grams of solute / grams of solution) * 100

grams of solute are obtained from the molar concentration:

M = (number of moles of solute) / (volume of solution in liters)

where number of moles = (grams) / (molar mass)

=> M = (grams of solute / molar mass of solute) / (volume of solution in liters)

=> grams of solute = M * (volume of solution in liters) * (molar mass of solute)

And density = (kg of solution / volume of solution in liters) =>

kg of solution = density * volume of solution in liters

grams of solution = density * (volume of solution in liters) * 1000 g/kg

=> mass percent = M * (volume of solution in liters) * (molar mass) / (density * volume of solution in liters * 1000 g/ kg) * 100

=> mass percent = M * molar mass * 10 / density

now replace the values known:

M = 0.0190 mol / liter
density = 1,000 kg / liter

molar mass of Ba(NO3)2 = 137.327 g/mol + 2*14.007 g/mol + 2*3*15.999 g/mol = 256.335 g/mol

=> mass percent = 0.0190 mol/liter * 256.335 g/mol * 10 kg/ g / (1.000 kg/liter)

=> mass percent = 48.7%

6 0

4 years ago