Physics practice problems?

Question

Not all of my questions are showing up;(

1. Tricia puts 44 g of dry ice (solid CO2) into a 2.0-L container and seals the top. The dry ice turns to gas at room temperature (20

Answer 1

1.

Mass of       = 44 grams.

Now converting grams into moles:

The atomic mass of  C is  12.01. 

The atomic mass of O is 16.00.

The formula mass of    =12.01 + 2 (16.00)  =12.01 +32 = 44.01 grams.

Thus 1 mole of      weighs 44.01 grams .This relation provides a conversion factor to go from  grams to moles.

Using the factor  1mole /44.01 grams

Moles  =  44 *  1 mol/44.01 grams = 0.99 moles.

Hence there are 0.99 moles in  44 grams of dry ice (solid  )

Volume of the container = 2.0 L

Room temperature = 20 + 273K = 293 K

Ideal Gas constant(R) = 8.314 J / K mole 

By using ideal gas equation P * V = m * R * T

                                =>P = (m * R * T) / V

Now substituting the values, P = (0.99 * 8.314 *293) / 2.0

                                        =(2411.6) /(2.0)

                                        =1205.8 Pa

Hence the pressure of    in the container is  1205.8 Pa.