8th Grade Unit 2 Review

Which of the following is a chemical symbol?

• 2H₂O --> 4H + O₂

• H₂O

• Co

• NaCl

Organize these options into the right categories

Groups:

(a) Chemical Symbol

,

(b) Chemical Formula

,

(c) Chemical Equation

• CO

• 2H₂O --> 4H + O₂

• 3CO₂

• 2Na₃O --> 2Na₂O + 2Na

• O

• H₃Na

• Co

• 4CaCO₃ --> 2Ca₂CO + O₂

• H

Tags

NGSS.MS-PS1-1

NGSS.MS-PS1-2

NGSS.MS-PS1-5

Look at the following formula - 3NaCl₄. Which number represents the subscript?

• 4

• 3

• 12

• 1

Look at the following formula - 3NaCl₄. How many Cl atoms are present?

• 4

• 3

• 12

• 1

Tags

NGSS.MS-PS1-1

Where do I find a subscript?

• The small number hanging below and after the element it affects

• The large number always before the molecule

Where do I find the coefficient?

• The large number always before the molecule

• The small number hanging below and after the element it affects

What does a subscript tell me?

• How many of the element it follows are present

• How many of the molecule is present

• How many total atoms of that element there are in the formula

Organize these options into the right categories

Groups:

(a) True Statement

,

(b) False Statement

• If coefficients and subscripts are present you must add them together

• The product is to the right of the equation arrow

• Coefficients are used different in formulas than they are in equations

• No subscript means only 1 of that element

• The reactant is to the left of the equation arrow

• The reactant is to the right of the equation arrow

• No coefficient means only 1 of that molecule

• The product is to the left of the equation arrow

Tags

NGSS.MS-PS1-5

What does the arrow ----> in a chemical equation mean?

• yields or produces

• go this way

• next or because of

• create

Which is the correct Law of Conservation?

• Matter cannot be created or destroyed, but it can change form

• Matter can be created or manipulated, and it can change form

• Matter cannot be created but it can be destroyed and change form.

• Matter can be renewed and replaced and it can change form

Tags

NGSS.MS-PS1-5