Chemistry Mart Sem 1 Set B

The mass percent concentration of a solute in a solution is defined as

• Grams of solute in 100 g solvent

• Grams of solute in 100 g solution

• Grams of solute in 100 ml solution

• Grams of solute in 100 kg solvent

The Bohr theory explains that an emission spectral line is due to

• an interaction between electrons in atoms

• an electron gaining energy and changing orbit

• an electron losing energy and changing orbit

• an electron losing energy but keeping the same value of its four quantum number

Which if the following trends occurs to the elements across the third period from sodium to chlorine in the periodic table?

• Size of atoms increases

• Electronegativity decreases

• The outer electrons are held more weakly

• Forces of attraction between electron and nucleus increase

Elements that has two single electrons and two pairs in its Lewis symbol

• Carbon

• Nitrogen

• Oxygen

• Flourine

Which of the following statement is TRUE for gases?

• The volume of a gas is directly proportional to the pressure

• The pressure of a gas is inversely proportional to its temperature

• The number of moles of a gas is directly proportional to the gas constant

• For a fixed mass of gas at a constant temperature, the volume of gas is inversely proportional to the pressure

Which of the following is an example of a crystalline solid?

• CsCl

• N₂

• NH₃

• O₃

Calculate the pH of a 0.02 M solution of Ca(OH)₂ at 25^oc

• 0.04

• 1.40

• 1.69

• 12.6

Choose the CORRECT statement regarding buffer solutions

• A buffer capacity is the pH of a buffer after mixing an acid and base pair in limited amount

• A buffer made from strong acid and strong base is normally able to resist changes in pH better

• A buffer solution made from NH₃ and NH₄Cl pair will have pH in the acid range

• A buffer is characterized by its pH, and its buffer capacity upon the addition of small amounts of strong acid or strong base

Which one of the following statements describes the metallic bonding?

• Metallic solid consist of cations

• Valence shell of atoms involved in the formation of metallic bond overlap to form negatively charged sea

• The strength of metallic bond declines with increasing number of electron involved

Choose the ALL correct statement(s) when the following mixture is compressed.

2Cl₂(g) + 2H₂O(g) ⇌ 4HCl(g) + O₂(g)

• Less HCl formed

• The rate of the reverse reaction increases

• The value of the equilibrium constant will decrease