初三和高一化学题目求解

1. 维生素药片包含维生素500g, 所以其中包含了多少摩尔和多少分子的维生素?

2. A sample of nitrogen gas has a volume of 1.75L at STP. How many mole of N2 are present?

3. Calculate the molecules of each of the following gasws all at STP.

 a. 0.2mol H2    b. 0.2g O2    c. 0.2L N2

   4.  Calculate the volume of each of the following gasws all at STP

a. 4.4g CO2     b. 0.71g CL2     C. 3.2g CH4

   5. A sample of gas has a density(密度) of 1.96g/L at STP. Determine its molar mass(摩尔质量)

   6. What mass of He is required to fill a 1.5L balloon at STP?（He-4）