Math in chemistry

Question 1

How do you calculate the number of significant figures in a number?

Answer 1

Significant figures is the number of digits in a number:
234 = 3 sig figs
2938 = 4 sig figs
219.384 = 6 sig figs
However trailing zeroes are not counted unless there’s a decimal point
8000 = 1 sig fig
8080 = 3 sig figs
8000. = 4 sig figs (because of the decimal point)
80,000.00 = 7 sig figs
Leading zeroes are also not counted
0.01 = 1 sig fig
0.001 = 1 sig fig
0.182 = 3 sig figs

Question 2

How do convert celsius to Fahrenheit?

Answer 2

F = 1.8c + 32
Example: 100 celsius to Fahrenheit = 1.8 * 100 + 32 = 212

Question 3

How do you calculate Fahrenheit to celsius?

Answer 3

C = (F - 32)/1.8
Example: 98 F –> C = 66/1.8 = 36.7 c

Question 4

How do you convert celsius to kelvin?

Answer 4

K = C + 273.15
Example: 7C –> K = 7 + 273.15 = 280.15

Question 5

How do you convert kelvin to celsius?

Answer 5

C = K - 273.15
Example: 283.15K –> C = 10

Question 6

How do you convert for Fahrenheit to kelvin?

Answer 6

K = (F-32)/1.8 + 273.15
Example: 200 F = 366.483 K

Question 7

How do you convert from kelvin to Fahrenheit?

Answer 7

F = (K - 273.15) * 1.8 + 32

Question 8

​How do you convert from feet to inches?

Answer 8

1ft = 12 in

Question 9

How do you convert from feet to yards?

Answer 9

3ft = 1yd

Question 10

How do you convert from inches to centimetres?

Answer 10

1in = 2.54cm

Question 11

How do you convert from kilometres to metres?

Answer 11

1km = 1000m

Question 12

How do you convert from metres to centimetres?

Answer 12

1m = 100cm

Question 13

How do you convert from mile to kilometres?

Answer 13

1mi = 1.609km

Question 14

How do you convert from miles to feet?

Answer 14

1mi = 5280ft

Question 15

How do you convert from kilograms to grams?

Answer 15

1kg = 1000g

Question 16

How do you convert from kilograms to pounds?

Answer 16

​1kg = 2.2lb

Question 17

How do you convert from pounds to ounces?

Answer 17

1lb = 16oz

Question 18

How do you convert from tons to pounds?

Answer 18

1 ton = 2000lb

Question 19

How do you convert from metric tons to kilograms?

Answer 19

1 metric ton = 1000kg

Question 20

How do you convert from metric tons to pounds?

Answer 20

1 metric ton = 2204lb

Question 21

How do you convert from litres to millilitres?

Answer 21

1L = 1000ml

Question 22

How do you convert from millilitres to cubic centimetres?

Answer 22

1mL = 1 cm^3

Question 23

How do you convert from cubic metres to litres?

Answer 23

1m^3 = 1000L

Question 24

How do you convert from gallons to litres?

Answer 24

1gal = 3.785L

Question 25

How do you convert from gallons to quarts?

Answer 25

1 gallon = 4 qt

Question 26

How do you convert from quarts to pints?

Answer 26

1 qt = 2 pints

Question 27

What’s the difference between accuracy and precision?

Answer 27

Accuracy is how close your answer is to the right answer
Precision is how much your data agrees with itself.

Question 28

How do you calculate density?

Answer 28

D = M/V

Question 29

How do you convert from atmospheric pressure to pascals?

Answer 29

1 atm (standard sea level) = 10135 pascals

Question 30

How do you convert from mL to grams given the density of the thing you’re converting?

Answer 30

G = (N. of mL) x (N. of grams per mL)