Unit 2-Chemical Changes

Question 1

balance chemical equations

Answer 1

hi

Question 2

what are the five pieces of evidence for a chemical change

Answer 2

Color change, 
formation of gas, 
precipitate, 
release or absorption of energy, 
new odour

Question 3

determine the type of reaction and predict the products

Answer 3

go

Question 4

endothermic versus exothermic

Answer 4

endothermic reactions require energy

exothermic reactions create energy

Question 5

what is the word equation for methane?

Answer 5

CH4

Question 6

what is another way to write H2O?

Answer 6

HOH

Question 7

define chemical change.

what happens in a chemical change?

Answer 7

A chemical change is a change in which at least one new substances formed, with different physical and chemical properties then the starting materials

New products are created

Question 8

synthesis

Answer 8

A chemical reaction in which two or more substances combine to form a more complex sentence

A+B=AB

Question 9

Decomposition

Answer 9

Chemical reaction in which compound is broken down into two or more simpler substances

AB=A+B

Question 10

combustion

Answer 10

The reaction of a substance with oxygen to produce oxides and energy

most commonly used to produce heat

Question 11

Combustion of a hydrocarbon produces…

Answer 11

H2O and CO2

Question 12

Single displacement

Answer 12

reaction of an element with the compound to bring us a new element and a new compound activity series will be used

A+BC=AC+B

Question 13

why is hydrogen placed with the metals on the activity series?

Answer 13

hydrogen acts like a metal so it is on the list of metals (loses electrons) it becomes positively charged

Question 14

how to use activity series

Answer 14

anything that is higher on the activity series will form the compound by displacement

Question 15

Double displacement

Answer 15

this is the reaction in which compounds rearrange and form new compounds.

solutions that may or may not have precipitates

AB+CD=AD+CB

Question 16

neutralization

Answer 16

a double displacement reaction between an acid and a base to produce an ionic compound (a salt) and water

Question 17

balancing

Answer 17

put a 1 before compounds with no number out front

Question 18

what occurs during a chemical change?

Answer 18

a new substance is created

bonds break or form because of their attractive forces

Question 19

endothermic and example

Answer 19

The reaction needs a continuous supply of energy put into the system
example copper he did over the Bunsen burner the reaction stopped when the heat stopped

Question 20

exothermic and example

find one

Answer 20

A reaction that releases much more energy then what was put into the system

Question 21

acid rain causes

Answer 21

factors that lead to acid rain are transportation, heating homes, and coal burning factories

Question 22

what is the equation for acid rain?

Answer 22

blank

Question 23

what are the five types of reactions?

Answer 23

synthesis, decomposition, combustion, single displacement, double displacement