Concept Refresher

Which of the following is an example of a molecule?

• A) a group of atoms bonded together

• 
• All of the above

What is the Law of Conservation of mass?

• Mass is created in a chemical reaction
• Mass is created in a physical change
• New chemicals formed from a chemical reaction have a larger overall mass than the original reactants
• Mass is never created or destroyed

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

The Coefficient (3) in the Chemical Formula, 3H₂O, tells you how many _____________ there are.

• Atoms of Hydrogen

• Atoms of Oxygen

• Atoms of Water

• Molecules of Water

Tags

NGSS.MS-PS1-1

The Subscript (2) in the Chemical Formula, 3H₂O, tells you how many _____________ there are.

• Atoms of Hydrogen

• Atoms of Oxygen

• Atoms of Water

• Molecules of Water

Tags

NGSS.MS-PS1-1

What is the law of conservation of mass?

• The amount of matter changes when reacted or changed.
• The mass of all reactants are changed during a physical or chemical change
• The mass of the reactants equals the mass of the products
• The mass of the products is different than the mass of the reactants.

Tags

NGSS.MS-PS1-5

Why must the number of each type of atom on the reactant side equal the number of each type of atom on the product side?

• This means the mass of the reactants equals the mass of the products, which follows the law of conservation of mass.

• This means that the mass of the reactants equals the mass of the products, which does not follow the law of conservation of mass.

The number in front of a compound or element is a

(for example: the item labeled "A" on the image attached)

• Subscript

• Coefficient

• Superscript

• Charge

The number to the lower side of an element is a

(for example: the item labeled "B" on the image attached)

• Subscript

• Superscript

• Coefficient

• Charge

Matter can not be created nor destroyed: it can only be

• Destroyed a little bit

• Invisible

• Transformed, changed, rearranged into a different form

• None of the above

A chemical reaction is balanced when

• both sides have the same elements
• Both sides have the same  number of atoms
• Same subscripts
• Same coefficients

Tags

NGSS.MS-PS1-5