Chemical reactions

Question 1

what is the difference between a phisical change and a chemical change. give examples

Answer 1

in chemical changes bonds break (burning paper) in phisical changes it just looks differnet then before (melting butter)

Question 2

what is the difference between an exothermic and endothermic reaction. give examples

Answer 2

exothermic produces heat (fire) endothermic needs heat to run (instent cold pack)

Question 3

give an exapmple that might seem like a chemical change but is actually a phisical change

Answer 3

melting buter

Question 4

what must happen to a molecule for a chemical change to occer

Answer 4

bonds must break

Question 5

can you change the subscript in a chempcal formula when balencing an eaquasion, why or why not

Answer 5

no you can only change the coeficient. if you cange a subscript you make a different substence

Question 6

what are 4 main changes you look for when trying to determine weather or not a chemical change occured

Answer 6

1. change in apperence
2. production of gas
3. production of precipitate
4. change in energy

Question 7

what are the names from left to right in a chemical formula

Answer 7

reactent, yeilds arrow, product

Question 8

what are the 4 main types of eaquasions and how are they written “genericly”

Answer 8

synthisis- A+B->AB
deconpisition- AB->A+B
single reaplacement- AB+C->AC+B
double reaplacement- AB+CD->AD+CB

Question 9

what does the law of concentration of matter state

Answer 9

ater cannot be created or distroyed just changed

Question 10

if you wanted to test if the law of concervation of matter is correct would you use an open or a closed system. why

Answer 10

closed so no gas can get out

Question 11

what are the 4 ways of controlling a reaction

Answer 11

1. surface area
2. concentration
3. temperature
4. catalyist and inhibitor

Question 12

why does an increase on temperature increase the reaction rate

Answer 12

the molecules are bouncing around faster so they touch what they are reacting to faster

Question 13

does an increase in surface area increase or deacrese the amount of time it takes for a reaction rate. why

Answer 13

increase because there are more molecules availible to start the reaction

Question 14

how does a deacrease in concentration affect the length or reaction. why

Answer 14

there is less to react with

Question 15

what is the difference between a catalyst and inhibitor . give an example of each

Answer 15

catalyst dtarts a reation faster (enzyme) inhibitor slows it down or prevents it from happening (a conservative)