Chemical Reactions

In a chemical equation, is it true that -

• the reactant side and product side can have different numbers of atoms for each element
• there can be different elements on the reactant side and the product side
• an element or compound must be accompanied by a phase change
• the coefficients indicate the number of molecules of each reactant used and the number of molecules of each product made

Tags

NGSS.MS-PS1-5

Which of the following models best demonstrates a balanced chemical equation?

• F
• G
• H
• J

Tags

NGSS.MS-PS1-5

The reactants are on the left side of the chemical equation.

• True
• False

Tags

NGSS.MS-PS1-5

How many atoms in all are in a molecule of serotonin?

C₁₀H₁₂N₂O

• 22
• 24
• 25
• 4

Tags

NGSS.MS-PS1-1

Coal contains carbon and other elements. Carbon dioxide forms when coal burns in the presence of oxygen. Which of these is the best evidence that a chemical reaction occurs when coal burns?

• The shape of the coal changes
• Oxygen is present
• A new substance is produced
• Coal is made up of more than one element

Tags

NGSS.MS-PS1-2

Is burning wood a chemical or physical change?

• chemical
• physical

Tags

NGSS.MS-PS1-2

Is glass breaking a chemical or phyiscal change?

• chemical
• physical

Tags

NGSS.MS-PS1-2

Is hammering wood together to build a house a chemical or physical change?

• chemical
• physical

Tags

NGSS.MS-PS1-2

Is a a rusting bicycle a chemical or physical change?

• chemcial
• physical

Tags

NGSS.MS-PS1-2

Is melting butter for popcorn a chemical or physical change?

• chemical
• physical

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-4