# science

posted by .

A mixture of two gases, C2H2 and H2, has the properties listed below.

nC2H2=0.028moles
nH2=0.015moles
PC2H2=79torr

What is the PT for this mixture?

I first found out the mole fraction by first adding H2 and C2H2 and got 0.043, then did 0.028/0.043. I rounded it to 0.651. I then set up my equation like this:

79 = (0.651)*Pt

i divided 79 by 0.651 (so the equation was like this: 76/0.651) and got 121 (rounded to nearest whole number). However, the answer was 120. What did I do wrong?

PS: My teacher never taught me this.

• science -

All numbers in the original data were given to two significant figures, so your answer cannot be expected to be more accurate. Rounding it to two significant figures (i.e. 120) would be appropriate.

Check that the answer is 120 and not 120. 120 means two significant figures, while 120. means 3 (wrong).

## Similar Questions

1. ### Chemsitry II

mole fraction is equal to partial pressure divided by the total pressure Total pressure= sum of partial pressure use PV=nRT where n= number of moles equation become PV/RT=n make sure to convert the temperature to Kelvin and to use …
2. ### science

A mixture of two gases, Xe and H2, has the properties listed below. PXe=190torr PT=250torr What is the ΧH2 for this mixture?
3. ### science

Listed below are six mixtures. Identify physical properties of the components that allow you to separate them. Then, explain the method you would use to separate the components. Mixture 1: Salt dissolved in water Physical Properties: …
4. ### Chemistry

A mixture of C3H8 and C2H2 has a mass of 2.0g . It is burned in excess O2 to form a mixture of water and carbon dioxide that contains 1.6 times as many moles of CO2 as of water. Find the mass of C2H2 in the original mixture.
5. ### Chemistry

A mixture of C3H8 and C2H2 has a mass of 2.6g . It is burned in excess O2 to form a mixture of water and carbon dioxide that contains 1.6 times as many moles of CO2 as of water. Find the mass of C2H2 in the original mixture.
6. ### Chemistry

A mixture of C3H8 and C2H2 has a mass of 2.6g . It is burned in excess O2 to form a mixture of water and carbon dioxide that contains 1.6 times as many moles of CO2 as of water. Find the mass of C2H2 in the original mixture.
7. ### Chemistry

A mixture of C3H8 and C2H2 has a mass of 2.3g . It is burned in excess O2 to form a mixture of water and carbon dioxide that contains 1.6 times as many moles of CO2 as of water. What is the mass of C2H2 in the original mixture?
8. ### Chemistry

A mixture of C3H8 and C2H2 has a mass of 2.5 g . It is burned in excess O2 to form a mixture of water and carbon dioxide that contains 1.5 times as many moles of CO2 as of water. Find the mass of C2H2 in the original mixture.
9. ### Chemistry

Oxyacetylene torches are fueled by the combustion of acetylene, C2H2. 2C2H2(g) + 5O2(g) --> 4 CO2(g) + 2H2O(g) If the enthalpy change for the reaction is -2511.14 kJ/molrxn, how much heat can be produced by the reaction of a. 2mol …
10. ### problem's on gay lussac's equation

on igniting a mixture of c2h2 and o2,200cc of co2 is formed.calculate the volume of c2h2 and o2 in the original mixture

More Similar Questions