Pure silver metal can be made using the reaction shown above; Cu + 2AgNO3 --> Ag + Cu(NO3)2. How many grams of copper metal will be needed to use up 100g of AgNO3?
A. 18.70g
B. 37.3g
C. 74.7g
D. 100g
Here is a solved example of a stoichiometry problem. Just follow the steps.
http://www.jiskha.com/science/chemistry/stoichiometry.html
To determine the amount of copper metal needed to use up 100g of AgNO3, we need to calculate the stoichiometric ratio between copper and silver nitrate.
Looking at the balanced equation:
Cu + 2AgNO3 → Ag + Cu(NO3)2
we see that 1 mole of copper (Cu) reacts with 2 moles of silver nitrate (AgNO3). To convert grams to moles, we need to know the molar mass of each substance.
The molar mass of copper (Cu) is approximately 63.55 g/mol.
The molar mass of silver nitrate (AgNO3) is approximately 169.87 g/mol.
To calculate the number of moles of copper required to use up 100g of AgNO3, we can use the following steps:
1. Calculate the number of moles of AgNO3:
Number of moles = mass / molar mass
Number of moles of AgNO3 = 100g / 169.87 g/mol
2. Use the stoichiometric ratio to find the number of moles of Cu:
Moles of Cu = (Moles of AgNO3) / 2
3. Calculate the mass of Cu:
Mass of Cu = Moles of Cu * molar mass of Cu
Let's calculate:
1. Number of moles of AgNO3 = 100g / 169.87 g/mol ≈ 0.5882 mol
2. Moles of Cu = 0.5882 mol / 2 ≈ 0.2941 mol
3. Mass of Cu = 0.2941 mol * 63.55 g/mol ≈ 18.70g
Therefore, the answer is A. 18.70g