Answer:
0.025g
Explanation:
Firstly, we need to write a balanced chemical equation.
Ca + 2H2O —-> Ca(OH)2 + H2
From the chemical equation, we can see that one mole of calcium metal yielded one mole of hydrogen gas.
Now, we need to know the actual number of moles of hydrogen gas given off.
The number of moles is the mass divided by the atomic mass. The atomic mass of calcium is 40g/mol. The number of moles is thus 0.5/40 = 0.0125 mole
Since the mole ratio is 1:1, the number of moles of hydrogen gas produced too is 0.0125 moles.
We now Proceed to get the mass of the hydrogen gas produced. This is the number of moles of hydrogen multiplied by the molar mass of the diatomic hydrogen gas. The molar mass of the diatomic hydrogen gas is 2g/mol.
The amount given off is thus 2 * 0.0125 = 0.025g
The much hydrogen that is produced is 0.02 mol of H₂ (answer B)
Explanation
2K +2H₂O→ 2 KOH + H₂
Use the mole ratio to determine the moles of H₂
From equation above the K :H₂ is 2:1
Therefore the moles of H₂ = 0.04 x 1/2 = 0.02 mol of H₂
It is given that the price of the carpet is $ 28.99 per square yard
Step 1: Convert square yard to square meter
1 square yard = 0.836 square meter
Step 2: Calculate the cost/square meter
Now based on the relation in step (1) we can write
0.836 square meter of carpet costs $ 28.99
Therefore the cost of 1 square meter of the carpet would be
= $ 28.99 * 1 sq meter/0.836 sq meter
= $ 34.68
Answer:
So oxidation reactions need not involve oxygen. This redox reaction is actually the sum of two separate half-reactions (a reduction half-reaction and an oxidation half-reaction).
