Chem

Question 1

what is an element?

Answer 1

a substance with only one type of atom

Question 2

what is a compound?

Answer 2

a substance with two or more types of atoms that ARE chemically bonded

Question 3

what is a mixture?

Answer 3

Substances that are made up out of two or more types of atoms but are NOT chemically bonded

Question 4

what is an atom?

Answer 4

the smallest unit of matter that retains its properties

Question 5

what is a molecule

Answer 5

a group of two or more atoms joined together

Question 6

what is a ion

Answer 6

atom or molecule with a charge

Question 7

describe the atoms in a liquid

Answer 7

they are still touching each other though they are in an irregular arrangement and are able to slide over each other

Question 8

describe the atoms in a solid

Answer 8

they are all touching being closely packed together, and are in a regular arrangement. They cannot freely move but they vibrate, they also have the strongest intermolecular force.

Question 9

describe the atoms in a gas

Answer 9

the particles are separated and move in fast speeds going in a straight line but randomly

Question 10

what is the Solvent

Answer 10

is the liquid that the Solute dissolves in

Question 11

what is the Solute

Answer 11

the solid that will be dissolved

Question 12

what is the Solution

Answer 12

the mixture that is created when the Solvent dissolves in the Solute

Question 13

how do you separate two miscible liquids on the basis of their boiling points?

Answer 13

fractional distillation

Question 14

what is Filtration used for?

Answer 14

to separate a insoluble solid from the Solvent (liquid)
it traps the residue (insoluble) as it allows the solute (liquid) to pass through

Question 15

what is the formula to calculate Rf value?

Answer 15

distance traveled by component/distance traveled by solvent

Question 16

why do you draw the base line in pencil?

Answer 16

because pen would smudge and pencil won’t because it is insoluble

Question 17

what are the characteristics of a physical change?

Answer 17

a usually reversible change in the physical properties of a substance, as size or shape

Question 18

what are the characteristics of a chemical change?

Answer 18

A Chemical Reaction is a process that occurs when two or more molecules interact to form a new product(s).

Question 19

what will you be left with in the process of evaporation

Answer 19

the solute

Question 20

why does solubility increase with temperature?

Answer 20

because kinetic energy increases, which allows the solvent particles to break up the solute particles more easily

Question 21

how does the atomic mass of an element affect its rate of diffusion

Answer 21

it diffuses faster

Question 22

how do you calculate the solubility?

Answer 22

an ex is 20 g of a substance dissolves in 200cm3 of water. the equation would be

20-200 x= 20x100/200 = 10
x-200

Question 22

what dose Evaporation and crystalisation do

Answer 22

it’s used to separate a soluble solid from a liquid. we use evaporation to turn the liquid into vapor leaving the solid behind.

Question 23

what is Fractional distillation used for

Answer 23

it is every similar to simple distillation, though it is used to separate substances with similar boiling points.

Question 24

what is simple distillation used for

Answer 24

its used to separate a liquid from a solid. its useful when we want to keep the liquid, separating substances with different boiling points