Chemistry

The compounds or elements present at the end of a reaction 

• reactants
• catalyst
• products
• energy 

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

The compounds and elements that are present at the beginning of a reaction:

• reactants
• catalyst
• products
• energy 

Tags

NGSS.MS-PS1-1

What is the law of Conservation of Mass?

• A measure of how much mass is created or destroyed. 
• Mass can neither be created nor destroyed during a chemical reaction. 

Tags

NGSS.MS-PS1-5

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

• Destroyed a little bit
• Invisible
• Transformed, changed
• None of the above

Tags

NGSS.MS-PS1-5

The number to the lower side of an element is a 

• Subscript
• Superscript
• Coefficient
• Charge

The coefficient in  3H₂O is

• 6
• 2
• 3
• 5

Tags

NGSS.MS-PS1-1

In a reaction A + B ----> C,  reactant A has 5g and product  C has 9g. How many grams does reactant B should have? 

• 4g
• 5g
• 9g
• 14g

Tags

NGSS.MS-PS1-5

What law states that, regardless of the amount, a compound is always composed of the same elements in the same proportion by mass?

• Law of definite proportions

• Law of conservation of mass

• Law of multiple proportions

• Law of mass action

If two or more compounds are composed of the same two elements, then the ratio of the masses of the second element that is combined with a certain mass of the first element is always a ratio of small whole numbers. This statement is called the law of

• definite proportions.

• conservation of mass.

• atomic theory.

• multiple proportions.

Who developed the Law of Conservation of Mass?

• Amedeo Avogadro

• Henri Becquerel

• John Dalton

• Demokritos

• Antoine Lavoisier

Tags

NGSS.MS-PS1-5