General Chemistry Answers

Express the concentration of solution in % w/v containing 12 g sodium chloride

and 50 ml of water.

A sample of oxygen gas occupies a volume of 250 mL at 750 torr pressure. What volume will it occupy at 900 torr pressure?

Given the reaction CH4 + 2O2→CO2 + 2H2O, what amount of O2 is needed to completely react with 14.0 moles CH4?

Using the integrated form of the rate law, determine the rate constant k of a zero-order reaction if the initial

concentration of substance A is 1.5 M and after 120 seconds the concentration of substance A is 0.75 M. what is the

half-life of substance A if its original concentration is 1.2 M?

 A 3.0-L bulb containing He at 145 mm Hg is connected by a valve to a 2.0-L bulb containing Ar at 355 mm Hg (see figure below). Calculate the partial pressure of each gas and the total pressure after the valve between the flasks is opened. [PHe = 87 mm Hg; PAr = 140 mm Hg]

An organic compound contains carbon(71,17%),hydrogen(5.12%) with the remainder nitrogen.Dissolving 0.177 g of the compound in 10 g of benzene gives a solution with a vapour pressure of 94.16 mmHg at 25°C .(The vapor pressure of pure benzene at this temperature is 95.26 mmHg.)What is the molecular formula for the compound?

Calculate the molar concentration of each of the following:

a. 6.0 N sulfuric acid (in reactions that replace both hydrogens)

b. 3.5 N potassium hydroxide

c. 4.0 N phosphoric acid (in reactions that replace two hydrogen ions)

d. 6.2 N sodium hydroxide

Calculate the percent concentration of each of the following solutions:

a. 2.50 N sodium hydroxide solution (density = 1.25 g/)

b. 4.80 N potassium hydroxide solution (density= 1.30 g/ m/)

A sample of oxygen at 44◦C occupies 373 mL.

If this sample later occupies 1102 mL at 60◦C

and 1.8 atm, what was its original pressure?

Answer in units of atm

Calculate the number of milliliters of solution required to provide the following:

a. 17.5 g of sulfuric acid from a 2.50 N solution in reactions that replace both hydrogen ions.

b. 24.2 g of calcium chloride from a 1.25 N solution in reactions that replace both chloride ions.