TEN: Chapter 3- Chemical Change

Question 1

Physical property

Answer 1

Properties that describe the physical appearance and composition of a substance
Change to a substance in which the composition of the substance stays the same
Ex:
Malleability, crystal shape, streak test, state, ductility, conductivity, solubility, mass, toxicity, volume, temp, color

Question 2

Chemical property

Answer 2

Properties that describe the reactivity of a substance

Change to a substance that always results in the formation of a different substance or substances

Question 3

Five clues to a chemical reaction occurrence

Answer 3

A new substance has been created, bubbles or a gas released, changing temp, colour change, a precipitate forms

Question 4

Exothermic reaction

Answer 4

A chemical reaction that releases energy, usually in the form of heat or light or electricity

Question 5

Endothermic reaction

Answer 5

Chemical reaction that absorbs energy

Question 6

Biochemical reactions

Answer 6

Maybe either endothermic or exothermic. Characteristics bio chemical reaction include reactions that are essential to life. Two important bio chemical reactions are photosynthesis and cellular respiration

Question 7

Photosynthesis

Answer 7

Means putting together with light
Photo-light
Synthesis-putting together
It is a chemical process in which carbon dioxide from the air and water from the soil, in the presence of light and energy that is glucose and oxygen

Question 8

Cellular respiration

Answer 8

Breakdown of glucose small molecules to release chemical energy that a cell can use

Question 9

Physical change

Answer 9

A change that doesn’t result in the change of the substance but how it looks

Question 10

Chemical change

Answer 10

A change that results in a completely different substance than the first

Question 11

Difference between a chemical and physical change

Answer 11

It’s can be in different states and look different if it is a physical change, whereas I chemical change results in a new substance

Question 12

The conservation of mass: Antoine Lavoisier

Answer 12

The total mass of reactants must equal the total mass of all the products

Question 13

A chemical reaction must contain the following

Answer 13

Correct formula for each reactant and product, physical state of each reactant and product, must be balanced

Question 14

Balancing guidelines

Answer 14

Start with the element that is the longest subscript, keep the polyatomic ion’s together if they appear on both sides of the reaction, leave elements until last, multiply to increase the number of Atoms or groups, write water as HOH in reactions that have the hydroxide ion in them, move back-and-forth as you balance

Question 15

Types of reactions: five

Answer 15

Formation, single decomposition, single replacement, double replacement, combustion and other

Question 16

Formation reactions

Answer 16

It shows the formation of a compound: element plus element equals compound

Question 17

Simple decomposition reactions

Answer 17

It is the opposite of formation:compound equals element plus element

Question 18

Single replacement reaction’s

Answer 18

They involve replacement of an element with an atom from a compact this will produce a new element and a new compound: if the element is a metal, it will exchange places with the positive ion in the compound by attaching
If the element is a nonmetal, it will exchange places with a negative ion by attaching itself to the positive ion
Element plus compound equals new element plus new compound
Note: polyatomic ion’s generally remain intact in a chemical reaction, water is generally written as HOH, if the reaction occurs in an aqueous environment use your solubility chart to predict the solubility of their ionic products of a single replacement reaction in water

Question 19

Double replacement reactions

Answer 19

Involves the exchange of ions between compounds. Usually the reactants are two compounds and the products or two compounds.
Compound plus compound equals new compound plus new compound
The ionic charges of each of the compounds get switched with one another so the compound starts with a positive and ends with a negative
These reactions can be further subdivided into neutralization and precipitation reactions

Question 20

Neutralization and precipitation reactions

Answer 20

Neutralization:Usually produce water as one of the products and the other is often assault of some kind
Precipitation: Produce one low solubility compound and one high solubility compound from 2 reactant compounds that are usually high solubility

Question 21

Combustion reactions

Answer 21

Element or compound plus oxygen equals some common oxides
Common oxides include: carbon dioxide, nitrogen oxide, sulphur dioxide, water
(CO2 NO2 SO2 H2O)
In this reaction a compound or element reacts with oxygen to form the most common oxides.
The most common oxides are:
If metal is combusted – use the ionic formula for that metal oxide
If hydrogen is combusted – H20 gas is produced
If nitrogen is combusted – NO2 gas is produced
If sulphur is combusted – S02 gas is produced
Almost always balance oxygen last

Question 22

Mole

Answer 22

Quantity that chemists use to measure elements and compounds
Symbol: mil
1 mol: 6.02 times 10 to the power of 23

Question 23

Molar mass

Answer 23

Mass of one mole of a substance
It is the mass number in the upper right corner of an element
G/mol

Question 24

Ionic

Answer 24

Metal plus no metal

Positive plus negative

Question 25

Molecular

Answer 25

Nonmetal plus non-mental

Negative plus negative

Question 26

Acid

Answer 26

Has hydrogen in it

Question 27

Determining the number of moles

Answer 27

Number of miles equals mass divided by molar mass (N= m divided by M
You first figure out the molar mass
You want it in grams not kilograms
Kilograms times 1000 to get grams

Question 28

Determining the mass from given number of moles

Answer 28

You look at the table to see the prefix used
First figure out the molar mass
You multiply the powered number by the given mass of moles in the equation and then cross multiply that with the molar mass to give you the mass in grams