Unit 2 Pre-Assessment

Front

What is the total number of atoms in one molecule of ammonia (NH₃)?

Back

4 atoms (1 Nitrogen and 3 Hydrogens)

Front

How many Magnesium atoms are in 10MgCl₂?

Back

10 Magnesium atoms

Front

What is the total mass of NaCl produced from the reaction 2Na + Cl₂ → 2NaCl if starting with 46 grams of Na and 71 grams of Cl₂?

Back

117 grams of NaCl

Front

How many different elements are present in H₂COCH₂?

Back

3 elements (Hydrogen, Carbon, and Oxygen)

Front

How many Hydrogen atoms are in 4H₂O?

Back

8 Hydrogen atoms

Front

Define a molecule.

Back

A molecule is a group of two or more atoms bonded together.

Front

What is the chemical formula for water?

Back

H₂O

Front

What is the principle of conservation of mass in a chemical reaction?

Back

Mass is neither created nor destroyed in a chemical reaction; the total mass of reactants equals the total mass of products.

Front

What does the subscript in a chemical formula indicate?

Back

The number of atoms of the element in one molecule.

Front

What is the difference between an element and a compound?

Back

An element is a pure substance made of one type of atom, while a compound is made of two or more different types of atoms chemically bonded.