Question

Which of the following statements is not correct?

0.20 mole of O2= 6.4 g

0.75 mole of H2CO3= 47 g

3.42 moles CO = 95.8 g

4.1 moles Li2O = 94 g

I need help please :/

Answer 1

This is chemistry. You might have a better time in the science department.

Answer 2

Crap I forgot v____v

Answer 3

But here's what you do.

Answer 4

I want you to get out a periodic table, and we'll look at the first answer :) I took Chemistry last year.

Answer 5

Okay hold on :D

Answer 6

So right now we're only going to look at H2CO3.

What this means is,
There are two Hydrogens, one Carbon, and three Oxygens.

We're going to look at the mass of each of these. It's the bottom row for each element's box. So for example, Hydrogen, its atomic mass is 1.0079.

Hydrogen: 1.0079
Carbon: 12.011
Oxygen: 15.999

Now we're going to round this for the sake of making multiplying easier.

Hydrogen: 1
Carbon: 12
Oxygen: 16

Understand so far?

Answer 7

Okay I have One

Answer 8

Yes I do

Answer 9

Okay, so because there's two Hydrogens, you're going to multiply the atomic mass by 2.

1(2) = H2

You're going to do this with all of them.
1(2) = H2
12(1) = C
16(3) = O3

Which equals;
2 = H2
12 = C
48 = O3

Answer 10

Okay so far so good

Answer 11

And then you're going to add all of this together to get the total amount of grams this is.

62g is your total.

Now, this is 62 grams per mole. And you need to see whether 0.75 of 62 grams is equal to 4, yeah?

Answer 12

Yes

Answer 13

Well, this means you need to see if 75% of it is equal to *47, I meant. What do you think you need to do to find 75% of 62?

Answer 14

I have no idea v__v chemistry and math are my worst subjects v___v

Answer 15

You're going to muliply it by 0.75 :) Plug that into your calculator and tell me what you get!

Answer 16

So multiply 0.75 and 62?

Answer 17

That's correct, thi will tell you 75% of 62.

Answer 18

*this

Answer 19

46.5 which will round up to 47 right?

Answer 20

Right. I love rounding with chemistry. It mamkes everything so much easier.

Answer 21

So that answer choice is true. You're going to use the same process for each of these answer choices, and one of them is going to be incorrect. That incorrect choice is your answer.

Answer 22

Okay Thank you :D

Answer 23

You're very welcome!