What amount of substance are: a) 0.8 kg of copper (II) oxide; b) 220 kg of sodium carbonate; c) 56 g of potassium hydroxide?

Problem 1
Given:
m (CuO) = 0.8 kg = 800 g

To find:
n (CuO) -?

Solution:
1) n (CuO) = m (CuO) / M (CuO) = 800/80 = 10 mol.

Answer: The amount of CuO substance is 10 mol.

Task 2
Given:
m (Na2CO3) = 220 kg = 220,000 g

To find:
n (Na2CO3) -?

Solution:
1) n (Na2CO3) = m (Na2CO3) / M (Na2CO3) = 220000/106 = 2075 mol.

Answer: The amount of Na2CO3 substance is 2075 mol.

Problem 3
Given:
m (KOH) = 56 g

To find:
n (KOH) -?

Solution:
1) n (KOH) = m (KOH) / M (KOH) = 56/56 = 1 mol.

Answer: The amount of KOH substance is 1 mol.