Question

In the reaction, CH4 + 2O2 arrow CO2 + 2H2O, 890 kilojoules of heat are released. Using Einstein's equation, calculate the mass amount to which this energy equates. (1 J = 1 kg m2 s-2) and the speed of light = 3.0 x 108 m/sec
Answer

9.9 x 1012 kg

9.9 x 10-12 kg

9.9 x 10-14 kg

1.1 x 10-6 kg

Answer 1

In the equation E = mc^2, what is m? In this case, that is.

Answer 2

@abb0t

Answer 3

@JFraser

Answer 4

m is what you're looking for, since the problem says "what mass"

Answer 5

E is given, 889kJ, and the speed of light is constant 3*10^8 m/s

Answer 6

oh...
m = E x c?

Answer 7

no

Answer 8

but where does the ^2 go?

Answer 9

since \[E = mc^2\] then \[ m = \frac{E}{c^2}\]

Answer 10

the squared function is part of the speed of light, you can't just ignore it when you rearrange an equation

Answer 11

ah....right..
sorry, I haven't had food yet, my brain's running on low with a subject it already has a hard time with.
so...
m = 890/3 x 108^2?

Answer 12

almost. the energy is given in kJ, but has to be in J for the equation. You actually have: \[m = \frac{8.89*10^5J}{(3.0*10^8\frac{m}{s})^2}\]

Answer 13

you have to be careful where your exponents are when you divide in scientific notation

Answer 14

hmm...
I got
8.001 x 10^22, which isn't an option..
confusion?

Answer 15

then your math is wrong, because you should get an incredibly small number

Answer 16

you should review how to manipulate scientific notation and the rules of multiplying and dividing with exponents

Answer 17

Oh, wait...no
I think the answer is B

Answer 18

do out the calculation and see

Answer 19

yeah, it's B, thnx for your help!

Answer 20

it is, GJ