Chemical Formulas and Counting Atoms

2H₂ + O₂ ----> 2H₂O What is the product?

• ------>

• 2H₂O

• 2H₂+ O₂

Tags

NGSS.MS-PS1-1

NGSS.MS-PS1-5

The law of conservation of matter states that

• chemical reactions change matter.

• in chemical reactions, the identity of reactants and products is conserved.

• atoms are neither created nor destroyed in chemical reactions.

• a chemical equation must be balanced.

Tags

NGSS.MS-PS1-5

Why is the following chemical equation not balanced?
H_{2 +} O₂ --> H₂O

• each side of the equation has a different number of oxygen atoms

• each side of the equation has a different number of hydrogen atoms

• each side has the same mass

Tags

NGSS.MS-PS1-5

Is the following equation balanced or unbalanced?
Fe + S --> FeS

• balanced

• unbalanced

Tags

NGSS.MS-PS1-5

What is the right ratio of chemicals for the BCE (Balanced Chemical Equation)?

• 2,1 --> 2,1

• 1,2 --> 1,1

• 1,2 --> 2,4

• 1,2 --> 2,1

Tags

NGSS.MS-PS1-5

What is the right ratio of chemicals for the BCE (Balanced Chemical Equation)?__CO + __Fe₂O₃--> __Fe + __CO₂

• 3,1 --> 2,3

• 3,2 --> 1,1

• 3,2 --> 2,4

• 3,2 --> 2,1

Tags

NGSS.MS-PS1-5

What is the part of the chemical equation in green called? 
Fe + S --> FeS

• products

• reactants

• yield

• chemical formula

What does the subscript in a chemical formula tell you?

• How many molecules are present

• How many atoms are present

• How many elements are present

• How many neutrons are present

How many atoms are there TOTAL in H₂SO₄ ?

• 6

• 5

• 7

• 3

Tags

NGSS.MS-PS1-1

How many Oxygen atoms are in Al₂(SO₄)₃?

• 4

• 12

• 7

• 24

Tags

NGSS.MS-PS1-1