# Units problem

1. Oct 9, 2004

### nemzy

What does (kg)(m/s^2) = what unit?

also does 1 cm^3= 1 mL?

i forgot all these units stuff its really bugging up my mind

2. Oct 9, 2004

### Pyrrhus

(kg)(m/s^2) = Newton

1 cm^3= 1 mL Yes

3. Oct 9, 2004

### nemzy

ok, im confused, ive been stuck on this problem for about an hour

So far i got this in my calculations:

(5.316 L*atm) / ( (211.68 kg*m/s^2)+(.0073m^2*atm))

the answer is suppose to be in meters, and from these units i have no idea how it is possible..anyone have any ideas?

4. Oct 9, 2004

### Pyrrhus

Show your work, by the way, L is liters right?

5. Oct 9, 2004

### nemzy

oh yeah and 1 more question, if u add units, then what happens?

like for example, if u have 8 atm + 3 liters, will it become 11 (atm+liters)?

6. Oct 9, 2004

### nemzy

k here is my work:

the equation is this:

h=n*R*T/(m*g+Po*A)

n= 1.85 moles
R=gas constant
T= 350 K
A= .00730 m^2
m= 21.6 kg

and Po is atmospheric pressure (1 atm or 1.0135e5 kPa)

7. Oct 9, 2004

### Spectre5

Absolutely Not!

8. Oct 9, 2004

### Pyrrhus

I don't believe you can do that, look up atm basic units, i mean Newton is kg*m/s^2, what is atm equal to? and use the relation above cm^3 = mL, and see if you can follow from that. This problems can be solved by converting to the same types of units, and simple elimination of analogous units.

9. Oct 9, 2004

### Spectre5

10. Oct 9, 2004

### Pyrrhus

a Pascal is N/m^2, use that. Also 1 atm = 101325 pascal.

11. Oct 9, 2004

### nemzy

ok, so i ended up with this:

5.315975 L*atm / (211.68 N +739.6725 m^2*Pa)

but i am stuck here, how can i cancel out further units? since the bottom is addition, i have no idea what to do from here...am i still allowed to convert the m^2 to liters and cance it out with the top, as well as the Pa with the atm on top?

12. Oct 9, 2004

### Spectre5

well, a pascal times m^2 is just Newtons!

so you have all newtons on the bottom....then instead of using that gas constant...use the one that is J * mol^-1 * K^-1

then you have J / N.....which is meters (change them to their base forms if you want to double check it :) )

13. Oct 9, 2004

### Pyrrhus

nicely done

14. Oct 9, 2004

### Spectre5

gas constant:

8.314 J * mol^-1 * K^-1

8.2057 L * atm * mol^-1 * K^-1

there are a few other forms of the gas constant too, but these are the most commonly used ones.

15. Oct 9, 2004

### nemzy

thx!! i finally got the right answer..this units are really bugging

does anyone know a website that has all these info?

16. Oct 9, 2004