Day 4 - Law of Conservation of Mass - EOG Review

Front

What is the Law of Conservation of Mass?

Back

Mass is never created or destroyed in a chemical reaction.

Front

What are subscripts in a chemical formula?

Back

Subscripts indicate the number of atoms of an element in a molecule, e.g., in Fe₂O₄, the subscripts are 2 and 4.

Front

Identify the coefficients in the equation 3H₂O.

Back

The coefficient is 3, indicating there are three molecules of water.

Front

Which chemical equation is balanced? 4O₂ + 2H₂ + S₂ ------ 2H₂SO₄

Back

This equation is balanced because the number of atoms of each element is the same on both sides.

Front

If an oreo cookie weighs 20 grams, how much do its crumbs weigh after being crushed?

Back

The crumbs still weigh 20 grams, demonstrating the Law of Conservation of Mass.

Front

What does a coefficient in a chemical equation represent?

Back

A coefficient represents the number of molecules or moles of a substance in a reaction.

Front

In the formula 3Fe₂O₄, what do the numbers 3 and 2 represent?

Back

3 is the coefficient indicating three molecules of Fe₂O₄, and 2 is the subscript indicating two iron atoms in each molecule.

Front

What happens to mass during a chemical reaction?

Back

The total mass of the reactants equals the total mass of the products.

Front

Why is it important to balance chemical equations?

Back

Balancing chemical equations ensures that the Law of Conservation of Mass is upheld.

Front

What is an example of a physical change that follows the Law of Conservation of Mass?

Back

Crushing a cookie into crumbs; the mass remains the same before and after.