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2 years ago

What is the mass in grams of 5.40 moles of lithium.

Chemistry

2 answers:

son4ous [18]2 years ago

6 0

Answer: The mass of lithium is 34.7 grams.

Explanation:

To calculate the mass of lithium for given number of moles, we use the equation:

$\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}$

We are given:

Number of moles of lithium = 5.40 moles

Molar mass of lithium = 6.94 g/mol

Putting values in above equation, we get:

$5.40mol=\frac{\text{Mass of lithium}}{6.94g/mol}\\\\\text{Mass of lithium}=(5.0mol\times 6.94g/mol)=34.7g$

Hence, the mass of lithium is 34.7 grams.

Maslowich2 years ago

3 0

You would use the formula:

n = $\frac{m}{M}$

Where m is the mass, and M is molar mass (the periodic table would be used for this)

In this case, we need to rearrange the formula to find m

m = nM
= 5.40 x 6.941
= 37.5g

Hope this helped! Ask me if there's any part of the working you don't understand :)

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bagirrra123 [75]

Answer:

NH3 is the limiting reactant

The % yield is 36.1 %

Explanation:

Step 1: Data given

Mass of NH3 = 2.15 grams

Mass of O2 = 3.23 grams

Molar mass of NH3 = 17.03 g/mol

Molar mass of O2 = 32 g/mol

volume of N2 produced = 0.550 L

Temperature = 295 K

Pressure = 1.00 atm

Step 2: The balanced equation:

4NH3 (aq) + 3O2 (g) → 2 N2 (g) + 6H2O (l)

Step 3: Calculate moles of NH3

Moles NH3 = Mass NH3 / Molar Mass NH3

Moles NH3 = 2.15 grams / 17.03 g/mol

Moles NH3 = 0.126 moles

Step 4: Calculate moles of O2

Moles O2 = 3.23 grams / 32 g/mol

Moles O2 = 0.101 moles

Step 5: Calculate the limiting reactant

For 4 moles NH3 consumed, we need 3 moles of O2 to produce, 2 moles of N2 and 6 moles of H2O

NH3 is the limiting reactant. It will completely be consumed ( 0.126 moles).

O2 is in excess, there will be 3/4 * 0.126 = 0.0945 moles consumed

There will remain 0.101 - 0.945 = 0.0065 moles of O2

Step 6: Calculate moles of N2

For 4 moles NH3 consumed, we need 3 moles of O2 to produce, 2 moles of N2 and 6 moles of H2O

For 4 moles NH3 , we'll have 2 moles of N2 produced

For 0.126 moles NH3 consumed, we'll have 0.063 moles of N2 produced.

Step 7: Calculate volume of N2 produced

p*V = n*R*T

⇒ with p = the pressure of the gas = 1.00 atm

⇒ with V = the volume = TO BE DETERMINED

⇒ with n = the number of moles N2 = 0.063 moles

⇒ with R = the gasconstant = 0.08206 L*atm/K*mol

⇒ with T = the temperature = 295

V = (nRT)/p

V = (0.063*0.08206*295)/1

V = 1.525 L = theoretical yield

Step 8: Calculate the % yield

% yield = actual yield / theoretical yield

% yield = (0.550 L / 1.525 L)*100%

% yield = 36.1 %

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2 years ago

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Answer:

20.79 kilojoules

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c = specific heat capacity of solid DMSO (1.80 J/g°C)

m = mass of DMSO

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Q = 50 × 1.80 × (250°C - 19°C)

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I did it step-by-step as the explanation but you can do all of this in one step.

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