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4 years ago

A sample of helium gas occupies 12.9 L at 315 K and 1.20 atm.

Chemistry

1 answer:

julsineya [31]4 years ago

5 0

Answer:

There are 0,6 moles of helium.

Explanation:

We use the ideal gas formula, we use the gas constant R = 0.082 l atm / K mol and we solve for n (number of moles) of the formula:

PV=nRT --> n= PV/RT

n= 1,20 atm x 12,9 L/ 0.082 l atm / K mol x 315 K= 0,599303135 moles

You might be interested in

What pressure in atmospheres(atm) is equal to 45.6 kPa?

postnew [5]

1 kpa = 0.0098692327 atm so just multiply that by 45.6

4 0

4 years ago

When 125 grams of FeO react with 25.0 grams of Al, how many grams of Fe can be produced? FeO + Al → Fe + Al2O3 25.9 g Fe 38.7 g

Serga [27]

Answer: The mass of iron produced will be 77.6 grams

Explanation:

To calculate the number of moles, we use the equation:

$\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}$ .....(1)

For FeO:

Given mass of FeO = 125 g

Molar mass of FeO = 71.8 g/mol

Putting values in equation 1, we get:

$\text{Moles of FeO}=\frac{125g}{71.8g/mol}=1.74mol$

For aluminium:

Given mass of aluminium = 25.0 g

Molar mass of aluminium = 27 g/mol

Putting values in equation 1, we get:

$\text{Moles of aluminium}=\frac{25.0g}{27g/mol}=0.93mol$

The given chemical reaction follows:

$3FeO+2Al\rightarrow 3Fe+Al_2O_3$

By Stoichiometry of the reaction:

2 moles of aluminium metal reacts with 3 mole of FeO

So, 0.93 moles of aluminium metal will react with = $\frac{3}{2}\times 0.93=1.395mol$ of FeO

As, given amount of FeO is more than the required amount. So, it is considered as an excess reagent.

Thus, aluminium metal is considered as a limiting reagent because it limits the formation of product.

By Stoichiometry of the reaction:

2 moles of aluminium metal produces 3 mole of iron metal

So, 0.93 moles of aluminium metal will produce = $\frac{3}{2}\times 0.93=1.395moles$ of iron metal

Now, calculating the mass of iron metal from equation 1, we get:

Molar mass of iron = 55.85 g/mol

Moles of iron = 1.395 moles

Putting values in equation 1, we get:

$1.395mol=\frac{\text{Mass of iron}}{55.85g/mol}\\\\\text{Mass of iron}=(1.395mol\times 55.85g/mol)=77.6g$

Hence, the mass of iron produced will be 77.6 grams

4 0

4 years ago

Use mathematics to prove that the 5.50 grams of salicylic acid (C7H6O3) used in this experiment is equal to 0.04 mol.

g100num [7]

Answer:

Please find the answer to the question below

Explanation:

In chemistry, the following mathematical formula is used to calculate the number of moles contained by a substance:

mole = mass of substance (g)/molar mass of substance (g/mol)

Molar mass of salicylic acid (C7H6O3) = 12(7) + 1(6) + 16(3)

= 84 + 6 + 48

= 138g/mol

Mass = 5.50grams

mole = 5.5/138

mole = 0.039

Approximately, the number of moles of 5.5grams of salicylic acid is 0.04moles. This is in accordance with the mole value (0.04) given in this question.

7 0

3 years ago

How many moles of carbon are in 6.0 moles of quinine

damaskus [11]

The molecular formula of quinine is C20H24N2O2. For every 1 mole of quinine molecule, there are 20 moles of carbon. Simply multiplying 6.0 moles by 20, we get, 120 moles.
Therefore, there are 120 moles of carbon in 6.0 moles of quinine.

4 0

4 years ago

Karl likes to use cruise control when he drives on

Yanka [14]

Answer:

3.96 MINUTES

Explanation:

Karl likes to use cruise control when he drives on

the highway. After setting cruise control at 33.53

m/s (75 mph). At this speed, how long would it

take Karl to travel 8 kilometers?

VELOCITY = DISTANCE/TIME

V=D/T

VT=D

T=D/V

THE DISTANCE IS 8 KM

THE VELOCITY IS 75 MPH

THERE ARE 1.61 KM PER MILE

75M[H =

75 X 1.61 KM/H =

121 KM/HR

T=D/V

T=8/121 =0.066 HOUR =

0.066 X 60 MINUTES =

3.96 MINUTES

CHECK

75 MPH =

(75 X 1.61) KM/60 MINUTES =

120,75 KM/60 MINUTES=

2.01 KM/MINUTE

to travel 8 K,M WILL TAKE

8/2.01 = 3.98 minutes

3 0

2 years ago