Knowledge Check -- Chemical Formulas

A chemical formula is provided. How many atoms of hydrogen (H) are found in this substance?

(NH₄)₂CO₃

• 2

• 4

• 6

• 8

Tags

NGSS.MS-PS1-1

A chemical formula is shown. The subscripts in a chemical formula represent the –

C₃H₂OH

• number of atoms of the element in front of the subscript.

• atomic mass of the heaviest element in the compound.

• atomic number of the element that follows the subscript.

• column on the Periodic Table of the element next to it.

Tags

NGSS.MS-PS1-1

Water H₂O is an example of a compound. Which of the following is the best description of all compounds?

• A substance that cannot be broken down into simpler substances

• A substance that is made up of more than one kind of atom

• A material that has a specific density at a specific temperature

• A group of atoms that have different abilities when joined together

Tags

NGSS.MS-PS1-1

The chemical equation shown represents a reaction that produces fuel for certain cars. Which substance represented in this equation is classified as an element?CO + H₂O --> CO₂ + H₂

• CO

• H₂O

• CO₂

• H₂

Tags

NGSS.MS-PS1-1

Which of these formulas contain equal numbers of nitrogen atoms?

• Formulas I and III

• Formulas II and III

  Formulas II and III

• Formulas I and IV

  Formulas I and IV

• Formulas I, II, and V

  Formulas I, II, V

Tags

NGSS.MS-PS1-1

In which of these compounds are there twice as many oxygen atoms as hydrogen atoms?

• H₃PO₄

• HClO₃

• H₂SO₄

• H₂O

Tags

NGSS.MS-PS1-1

The Law of Conservation of Mass states

• that matter exists in all states and reacts the same

• that matter exists in the same state throughout any chemical change

• that matter can only be changed into new substances by introducing a catalyst

• that matter cannot be created or destroyed and that the mass of the products must equal the mass of the reactants

Tags

NGSS.MS-PS1-5

The red numbers in the image below represent _______

• subscripts

• coefficients

• sub-efficients

• Coscripts

Tags

NGSS.HS-PS1-7

The substances at the beginning of a chemical equation are called the ____

• product

• yield

• chemical symbol

• reactants

Na + MgF₂ --> NaF + Mg

What are the reactants?

• Na + MgF₂

• NaF + Mg

• Na

• NaF