How many sodium ions are present in 50.0 mL of 0.210 M Na2S solution? (Show work for full credit)

How many moles of Ar are contained in a 5.00 L tank at -155°C and 2.80 atm? (R = 0.0821 L atm / mol K)

The volume of 350. mL of gas at 25°C is decreased to 135 mL at constant pressure. What is the final temperature of the gas?

5’ATAGGGCTT3′ is a short sequence of a strand of DNA. What will be the sequence of the complementary strand of DNA?

How many moles of Ar are contained in a 5.00 L tank at 155°C and 2.80 atm? (R = 0.0821 L atm / mol K)

Ca3(PO4)2 + 5C –> 3CaO + 5CO + 2P   If 5.33 g of phosphorus is recovered from the reaction of 65.6 g of Ca3(PO4)2 what is the percent yield?  

A balloon filled with helium gas at 20°C occupies 4.91 L at 1.00 atm. The balloon is immersed in liquid nitrogen at -196°C, while the pressure is raised to 5.20 atm. What is the volume of the balloon in the liquid nitrogen?

A balloon filled with helium gas at 20°C occupies 4.91 L at 1.00 atm. The balloon is heated to 250°C, while the pressure is raised to 5.20 atm. What is the volume of the balloon after this treatment?

5’ATAGGGCTT3′ is a short sequence of a strand of DNA. What will be the sequence of an mRNA molecule produced by using this strand as a template?

What is the volume of 11.0 g of O2 at 7.78 atm and 80 oC? (Show your work for full credit) R= 0.0821 (L atm/mol K)