Intro to Chem (slides)

Question 1

Chemical Reactions:

Answer 1

bonds btwn atoms of substances are broken/ rearranged and new bonds are formed—froming new substances w/ dif. properties

Question 2

A chemical reaction is represented by a:

Answer 2

chemical equation

Question 3

What are two parts of chemical equation?

Answer 3

Original substances -Reactants
resulting substances -products

Question 4

Reactant:

Answer 4

-substances that combine
-to the left

Question 5

Products:

Answer 5

-substances formed
-right

Question 6

-> =

Answer 6

yields

Question 7

Indications of a Chemical reaction (4):

Answer 7

-Energy change (heat, light)

-Production of gas (bubbles, fizz, smoke)

-Change in color

-Formation of a precipitate

Question 8

Precipitate:

Answer 8

Solid that is produced as a result of a chemical reaction in a sol. and that separates from the solution

Question 9

Physical Change:

Answer 9

change of state/phase (melting, freezing, condensing, etc)
+ same substance is still present but in diff. physical state

Question 10

Dissolving:

Answer 10

(physical change) Substance still present - dissolved in a solvent + can be seperated

Question 11

LAW of Conservation of Mass:

Answer 11

Atoms are neither created nor destroyed in ordinary chemical reactions (just rearranged)
-Same # of atoms on both sides
-Equation must be Balanced

Question 12

Why does an equation need to be balanced?

Answer 12

to correctly describe a reaction

Question 13

Coefficient:

Answer 13

’s placed in front of a symbol or formula and are used to balance an equation ex. 2H

Question 14

Coefficent =

Answer 14

molecules

Question 15

Subscript =

Answer 15

atoms