Based on the chemical reaction below, answer the following questions:
2NH3 + 3CuO ---> 3Cu + N2 + 3H2O
1. How many grams of CuO are needed to make 1500.0mL of at N2 STP?
Answer: 5625g
2. How many moles of Cu are produced when 12.50g of NH3 are used at 1000mmHg and 30 degrees Celsius?
Answer: 18.75
3. Determine the mass of all the products produced when 5mol of CuO is used during the reaction.
Answer:11.67
1 mole fills 22.4L at STP
so you want 1.5/22.4 = 0.06697 moles of N2
The equation says you will need 3*.06697 = 0.2 moles of CuO = 15.91g
Hmmm. Care to show your calculations?
To answer these questions, we need to use stoichiometry, which is a technique that relates the quantities of substances in a chemical reaction. Here's how to find the answers step by step:
1. How many grams of CuO are needed to make 1500.0 mL of N2 at STP?
To find the amount of CuO needed, we need to convert the volume of N2 gas to moles and then use the reaction stoichiometry to determine the corresponding amount of CuO.
First, convert the given volume of N2 gas to moles using the ideal gas law:
PV = nRT
Where:
P = pressure in atm (STP has a pressure of 1 atm)
V = volume in L (convert 1500.0 mL to L by dividing by 1000)
n = moles of gas
R = gas constant (0.0821 L·atm/(mol·K))
T = temperature in Kelvin
Plugging in the values:
1 atm × (1500.0 mL / 1000 mL/ L) = n × (0.0821 L·atm/(mol·K)) × (273 K)
Solving for n:
n ≈ 0.065 mol N2
Now, we can use the stoichiometry of the chemical reaction to find the amount of CuO:
From the balanced chemical equation, we can see that 2 moles of NH3 react with 3 moles of CuO to produce 1 mole of N2. Therefore, the ratio of moles of CuO to moles of N2 is 3:2.
Using this ratio:
(3/2) × 0.065 mol N2 = 0.0975 mol CuO
Finally, we can calculate the mass of CuO using its molar mass (79.55 g/mol):
Mass of CuO = 0.0975 mol × 79.55 g/mol = 7.77 g CuO (rounded to two decimal places)
Therefore, 1500.0 mL of N2 gas at STP requires approximately 7.77 grams of CuO.
2. How many moles of Cu are produced when 12.50 g of NH3 are used at 1000 mmHg and 30 degrees Celsius?
To find the moles of Cu produced, we need to use the same stoichiometry and reactant conversions.
First, convert the given mass of NH3 to moles:
Molar mass of NH3 = 17.03 g/mol
Moles of NH3 = 12.50 g ÷ 17.03 g/mol = 0.7345 mol NH3
From the balanced chemical equation, we can see that 2 moles of NH3 produce 3 moles of Cu. Therefore, the ratio of moles of Cu to moles of NH3 is 3:2.
Using this ratio:
(3/2) × 0.7345 mol NH3 = 1.1018 mol Cu
Thus, approximately 1.1018 moles of Cu are produced when 12.50 g of NH3 are used.
3. Determine the mass of all the products produced when 5 mol of CuO is used during the reaction.
From the balanced chemical equation, we can determine the stoichiometry between CuO and the products (Cu, N2, and H2O).
Based on the stoichiometry, 2 moles of NH3 react with 3 moles of CuO to produce 3 moles of Cu, 1 mole of N2, and 3 moles of H2O.
Therefore, if 2 moles of NH3 react with 3 moles of CuO to produce 3 moles of Cu, we can set up a proportion to determine the moles of Cu that can be produced from 5 moles of CuO:
(3/2) × 5 mol CuO = 7.5 mol Cu
Using the molar mass of Cu (63.55 g/mol), we can determine the mass of Cu generated:
Mass of Cu = 7.5 mol Cu × 63.55 g/mol = 476.63 g Cu
Similarly, we can use the stoichiometry to determine the moles of N2 and H2O produced:
1 mol N2 is produced per 2 mol NH3 used:
1/2 × 5 mol NH3 = 2.5 mol N2
3 mol H2O is produced per 2 mol NH3 used:
3/2 × 5 mol NH3 = 7.5 mol H2O
Using the molar masses of N2 (28.01 g/mol) and H2O (18.02 g/mol), we can calculate their masses:
Mass of N2 = 2.5 mol N2 × 28.01 g/mol ≈ 70.03 g N2
Mass of H2O = 7.5 mol H2O × 18.02 g/mol ≈ 135.15 g H2O
Therefore, when 5 mol of CuO is used during the reaction, approximately 476.63 g of Cu, 70.03 g of N2, and 135.15 g of H2O are produced.