General Chemistry Answers

Calculate for the amount of heat (kJ) that was liberated when 5.00 g of Mg(s) reacts with O2(g) at constant pressure. The heat of reaction is -1204 kJ / 2 mol of Mg (MW = 24 g/mol).

Tungsten (MW = 183.84 g/mol) crystallizes in a body centered cubic crystal lattice with a unit cube side length is 3.16 Angstrom. What is the density of the metal?

How many moles of carbon dioxide (MW = 44.0 g/mol) is produced when 150.0 grams of pentane (MW = 72.0 g/mol) is burned completely in air?

The percentages of aqueous sugar solutions with different concentrations which are separated by a semipermeable membrane are given below.For each of the situations below,indicate the flow of water in osmosis

2% sugar             5%sugar              9% sugar             20% sugar

1% sugar             7% sugar             5% sugar             205 sugar

1.Why do fingers look like prunes after swimming in a swimming pool after several hours?

2.What happens to the sixe of a small piece of sliced mango if it is immersed in a 10% salt and vinegar solution?Why?

B.Calculate the boiling point and freezing point of the following solutions:

1.0.575 molal aqueous solution

2.10 g of C6 H12 O6 dissolved in 259 g of water

3.0.5 mole Br2 dissolved in 507 g chloroform

D.A solution of propylene glycol (antifreeze) in the car’s radiator has a freezing point of -20 degree celcius.What is the molarity of the solution?

E.The boiling point of an aqueous solution is 102.5 degree celcius. What is the freezing point of the solution?

B.Calculate the boiling point and freezing point of the following solutions:

1.0.575 molal aqueous solution

2.10 g of C6 H12 O6 dissolved in 259 g of water

3.0.5 mole Br2 dissolved in 507 g chloroform

The boiling point of an aqueous solution is 102.5 degree celcius. What is the freezing point of the solution?

A solution of propylene glycol (antifreeze) in the car’s radiator has a freezing point of -20 0C.What is the molarity of the solution?

Calculate the Boiling Point of solution containing 6.5 g KOH (molar mass =56.11 g/mole) dissolved in 450 g of water.

What wavelength, in nm, can strike a metal surface and eject an electron at 1.89 x 10^-19 K if the binding energy of the metal is 289 kJ/mol

A miner discovered some yellow nuggets at the bottom of a shallow stream. The nuggets weighed 96.5 grams and had a volume of 5 ml. Were the nuggets gold or “ fool’s gold”(pyrite)? The density of gold is 19.3 g/ml and that of pyrite is 5 g/ml at 20 degrees Celsius. Show your calculations to justify your answer.

CH₄ +2 O₂ = CO₂ + 2 H₂O

You burned 15.0 grams of methane (CH4) in an excess of oxygen and formed 23.8 grams of water. What was your percent yield, rounded to 3 sig-figs?