Calculate the mass of chromium produced from 5 kg of Cr2O3.

3421.34 g

Explanation:

2Cr2O3 → 4Cr + 3O2  

From the  equation abve;

2 mol of Cr2O3  produces 4 mol of Cr

Converting 5 kg of Cr2O3 to mol;

Number of moles = Mass / Molar mass = 5000 / 151.99 g/mol = 32.9 mol

2 mol = 4 mol

32.9 mol = x

Solving for x;

x = 32.9 * 4 / 2

x = 65.8 mol

Mass = Number of moles * Molar mass

Mass = 65.8 * 51.9961

Mass = 3421.34 g

answer: c. the experiment shows that the red substance experienced a chemical change.

explanation: chemical change is the change in which chemical composition of the substance changes. physical change is the change in which there is no change in chemical composition.

chemical changes are accompanied by following changes:

a) precipitate formation

b) energy is released or absorbed

c) formation of bubbles

d) change in color

as it is given that the red color has disappeared and there is production of gas, it means the red substance has undergone a chemical change.

e