Question

The mass of the ocean is about 1.8 X 10^21 kg. If the ocean contains 1.076% sodium ion, Na+, what is the mass in kilograms of sodium in the ocean?

Answer 1

do you know the mass of sodium?

Answer 2

22.989769

Answer 3

??

Answer 4

I dont think so

Answer 5

hmmm okay

Answer 6

We know the ocean weighs 1.8 X 10^21 kg and 1.076% of its mass is sodium ions

we need to divide 1.076% by 100 to convert it to a decimal

Answer 7

than we multiply that by the weight of the ocean to find the mass of sodium in kilograms

Answer 8

okay

Answer 9

https://www.wolframalpha.com/input/?i=+%281.8+X+10^21%29*%281.076%2F100%29

Answer 10

you will probably want to put that in scientific notation

Answer 11

Do you follow?

Answer 12

so 0.01076?

Answer 13

for the very first part dividing by 100

Answer 14

We divide the percentage by 100 to convert it to a decimal.

Answer 15

Percentage is really just used because it is easier to look at round numbers than it is decimals

Answer 16

yeah i see it on the website okay

Answer 17

When ever you deal with a percentage you need to convert it back to a decimal

Answer 18

by dividing by 100 to use it

Answer 19

also always be mindful of your answer, if the ocean is massive 1% of the ocean should also be pretty massive so you should get a very large weight for the sodium ions

Answer 20

so 1.9368 x 10^19 kg

Answer 21

looks about right

Answer 22

you need to take significant figures to

Answer 23

so you should have 1.9*10^19

Answer 24

Our original numbers are not accurate past one decimal place