General Chemistry Answers

One gram of sodium hydroxide pellets is dissolved in two hundred-fifty milliliters water. What is the molarity, molality and normality of the solution? How much final solution is formed in terms of grams, milliliters and total number of moles? Assume the density of solution to be approximately that of water and the density of sodium hydroxide pellets to be 2.13 g/cc.( 4 decimal places)

Consider the reaction below. How much heat is evolved when 186 g oxygen are reacted with excess hydrogen? 2H2(g)+O2(g)⟶2H2O(g) ΔH=−572 kJ

a. - 106 kJ

b. - 3.32 kJ

c. - 98.4 J

d. - 3400 kJ

A serving size of six cookies contains 4 g of fat, 20 g of carbohydrates, and 2 g of protein. If walking 1.0 mile consumes 170 kJ of energy, how many miles must you walk to burn off enough calories to eat six cookies? Assume the energy content of fats, carbohydrates, and proteins are 8 kcal/g, 4kcal/g, and 4 kcal/g, respectively.

The enthalpy of combustion of solid carbon to form carbon dioxide is -393.7 kJ/mol C, and the enthalpy of combustion of carbon monoxide to form carbon dioxide is – 283.3 kJ/mol CO. Use these data to calculate ∆H for the reaction: *

a. +220.8 kJ

b. -220.8 kJ

c. - 338.5 kJ

d. -667.0 kJ

A balloon filled with 39.1 moles of helium has a volume of 876 L at 0.0°C and 1.00 atm pressure. The temperature of the balloon is increased to 38.0°C as it expands to a volume of 998 L, the pressure remaining constant. Calculate the ∆E. (Molar heat capacity of He is 20.8 J/mol °C). 

a. 111 kJ

b. 18.5 kJ

c. - 4.64 kJ

d. 43.3 kJ

What is final volume of the gas performing 575 J of work against an external pressure of 35.4 atm? The gas was originally at 27.5 L. 

a. 27.3 L

b. 43.7 L

c. 27.7 L

d. 11.3 L

A gas in a 70 L sturdy metal tank was subjected against an external pressure of 40 atm. Calculate the work done by or on the gas.

a. 3 L atm

b. Lacks information

c. -300 kJ

d. 0 kJ

A 100-kg body moving at 35 kph was found to have a total energy of 570 J. How much potential energy was there in the moving body?

a. 84 J

b. 490 J

c. 1.1 kJ

d. 55 J