General Chemistry Answers

. A gas filled a 5 dm3 container at a pressure of 3.0 atm, at 301 K. If the pressure of the system is doubled, what is the new volume that the gas will occupy at 301 K

Water is softened on a large scale for industrial use by precipitating calcium ions as solid calcium carbonate. This is achieved by reacting the calcium ions with sodium carbonate. Write out the net ionic equation for this reaction.

A gas at 40 oC, occupies a volume of 60 cm3 . What volume would the same gas occupy at 55 oC, at the same pressure

Using the kinetic particle theory, describe the interconversion between the three physical states of water.

Assuming that tap water contains the maximum acceptable concentration of lead (0.010 ppm), what is the mass of lead in a 270 L bathtub full of water? Show your work.

A. Using the following standard reduction potentials: Ag+ (aq) + e- ⇌ Ag (s) E o = +0.80 V Pb2+ (aq) + 2e - ⇌ Pb (s) Eo = -0.13 V i. Write a balanced redox reaction that represents the overall cell reaction for the feasible galvanic cell. ii. Calculate the standard cell potential. iii. Draw a fully labelled galvanic cell for this redox system. Your labels should show (but not limited to): the electron and ion flow; the anode and cathode, the half cells where oxidation and reduction take place. B. Describe the process involved in electroplating a silver coin.

Determine the direction the reaction will proceed to counteract these stresses AND establish how the concentration of fluorine (F₂) is expected to change.

ii. 1.5 x 10^-3 mol dm^-3 and 3.0 x 10^-3 mol dm^-3 of hydrogen and fluorine gas, respectively, were present in a closed system at 285 ^oC. At equilibrium, it was found that the concentration of hydrogen fluoride (HF) was 2.8 x 10^-3 mol dm^-3 . Calculate the value of K_c at 285 ^oC.

iii. What physical factor will change the value of K_c for this reaction.

Write the electron configuration using orbital notation, for:

i. He

ii. Na⁺

iii. O^2-

iv. Cu

i. What is meant by first ionization energy?

ii. Using calcium as an example, write a balanced chemical equation to illustrate first ionization energy.

iii. State and explain the general variation in first ionization energy going from sodium to argon, across Period 3.

Differentiate between the following types of bonds, using an illustration in each case to assist in your answer. i. Metallic bonding ii. Hydrogen bonding iii. Ionic bonding (6 marks) B. i. State THREE (3) properties of covalent compounds. (3 marks) ii. Draw the Lewis structure for the molecule of ammonia (NH3). (2 marks) iii. State the geometry of, and the bond angles in, the ammonia (NH3) molecule. (2 marks) iv. PH3 has the same geometry as NH3, however, the bond angle in PH3 is less than that in NH3. Provide an explanation for this observation. (3 marks) C. i. Define the term ‘electronegativity.’ (2 marks) ii. Explain how the concept of electronegativity relates to bond polarity. (2 marks)