Chemistry Answers

Calculate the H3O+ concentration for each pH.

pH=11[H3O+]= 

pH=2[H3O+]= 

pH=5[H3O+]=

Complete these Brønsted–Lowry reactions.

HCO−3+H+↽−−⇀

HCO−3+OH−↽−−⇀

Complete and balance the three equations according to acid and base behavior in water. Phase labels are optional.

HNO3(aq)+H2O(l)⟶

Ba(OH)2(s)−→−−H2O

HF(aq)+H2O(l)↽−−⇀

Give the name for the acid with the formula H3PO4 .

How would you prepare 500ml of 28% w/v (weight/volume) KOH (potassium hydroxide) solution? From this stock, how would you prepare a 0.1M working solution?

The characteristic odor of pineapple is due to ethyl butyrate. Combustion of 2.78 mg of ethyl butyrate yields 6.32 g of CO2 and 2.58 g of H20. The property of the compound suggest that the molar mass should be between 100 and 150g/mol. What is the molecular formula?

A flask is charged with 2.00 atm of nitrogen dioxide and 1.00 atm of dinitrogen tetroxide at 25 °C and allowed to reach equilibrium. When equilibrium is established, the partial pressure of NO2 has decreased by 1.24 atm. 

(a) What are the partial pressures of NO2 and N2O4 at equilibrium? 

(b) Calculate and for Kp and Kc following reaction at 25 °C.

2NO2 (g) ↔ N2O2 (g)

(Answer: K p = 2.80; K c = 68.6)

How many molecules of hydrochloric acid (HCI) are required to react with 10.0

grams of zinc (Zn)?

7. Carbon absorbs energy at a wavelength of 150.0 nm. The total amount of energy emitted by a carbon sample is 1.98 x 105 J. Calculate the number of carbon atoms present in the sample, assuming that each atom emits one photon.

The specific heat capacity for silver is 0.24 J/goC. Calculate the energy required to raise the temperature of 150.0 g Ag from 273 K to 298 K.