Answer:
Mass of hydrogen gas evolved is 0.0749 grams.
Explanation:
Total pressure of the gases = p = 758 mmHg
Vapor pressure of water = 23.78 mmHg
Pressure of hydrogen gas ,P = p - 23.78 mmHg = 758 mmHg - 23.78 mmHg
P = 734.22 mmHg = 
Temperature of of hydrogen gas ,T= 25°C =298.15 K
Volume of hydrogen gas = V = 0.949 L
Moles of hydrogen gas =n
PV = nRT (Ideal gas equation )
n = 0.03745 mol
Moles of hydrogen gas = 0.03745 mol
Mass of 0.03745 moles of hydrogen gas = 0.03745 mol × 2 g/mol = 0.0749 g
Mass of hydrogen gas evolved is 0.0749 grams.
Answer:
0.49 mol
Explanation:
Step 1: Write the balanced equation
Mg + 2 HCI ⇒ MgCl₂ + H₂
Step 2: Calculate the moles corresponding to 12 g of Mg
The molar mass of Mg is 24.31 g/mol.
Step 3: Calculate the moles of H₂ produced by 0.49 moles of Mg
The molar ratio of Mg to H₂ is 1:1. The moles of H₂ produced are 1/1 × 0.49 mol = 0.49 mol.
Answer:
0.712 mol
Explanation:
The easiest way to do this is to use a proportion.
1 mol of copper = 63.5 grams (check this using your periodic table).
x mol of copper = 45.2 grams
1/x = 63.5 / 45.2 Cross multiply
63.5 x = 1 * 45.2 Divide by 63.5
x = 45.2/63.5
x = 0.712 mol Answer to 3 sig digs
Answer:
64J of energy must have been released.
Explanation:
Step 1: Data given
One reactant contains 346 J of chemical energy, the other reactant contains 153 J of chemical energy.
The product contains 435 J of chemical energy.
Step 2:
Since the energy is conserved
Sum of energy of Reactants = Energy of Products
Sum of energy of Reactants = 346 J + 153 J = 499 J
The energy of the product = 435 J
435 < 499
This means energy must have been lost as heat.
Step 3: Calculate heat released
499 J - 435 J = 64 J
64J of energy must have been released.
