Experimental techniques C2

Question 1

dependent variable

Answer 1

reflects on the changes we make

Question 2

independent variable

Answer 2

constant, what we change

Question 3

precise results

Answer 3

values are close together (close to one point)

Question 4

SI units

Answer 4

standard units to measure

Question 4

control variable

Answer 4

variables where needed to be controlled to make a fair practical

Question 5

accurate results

Answer 5

close to actual value (middle of target)

Question 6

filterations

Answer 6

separate insoluble solid form liquid

Question 7

mixture

Answer 7

substances mixed, but not chemically joined

Question 8

evaporation

Answer 8

separate soluble solid from liquid

Question 9

pure

Answer 9

only have one substance present

Question 10

imoure

Answer 10

have more than one substance

Question 11

differences shown in graphs : pure impure

Answer 11

pure has straight line when changes state, impure has a slant when changes state.
due to the differences in melting points between the substances

Question 12

crystal

Answer 12

small, regularly shaped solids that reflect light

Question 13

crystalasation

Answer 13

substance forming a crystal

Question 14

distillation

Answer 14

separation of liquids and soluble solids using boiling

Question 15

fractional distillation

Answer 15

separating 2 or more different liquids by boiling in a certain temperature letting 1 liquid to serparate

Question 16

chromotography

Answer 16

separate small quantities of substances from a solution

Question 17

explain mobile phase and stationary phase

Answer 17

stationary phase : doesn’t move ex. paper
mobile phase : moves the solvent ex. water

Question 18

Rf value

Answer 18

Rf = distance moved by spot (substance that is measured) from base line / distance moved by solvent (water, mobile phase) from base line