Chapter 2 Test
What is the difference between an electrically neutral atom and an ion?
An ion has an unequal number of protons and electrons, while a neutral atom has an equal number.
What differentiates an organic compound from an inorganic compound?
An organic compound contains carbon
Which description best illustrates the product of a chemical reaction?
It is generally written on the right side and is the substance generated by the reaction
Which event illustrates evaporative cooling?
sweat evaporating from the skin
Which substance is an example of a very strong acid?
lemon juice
How many molecules are present in one mole of C6H12O6?
6.02 × 10^23 molecules
How can we identify a particular element?
By its number of protons
What is the OH− concentration of a solution having a pH of 2?
1 × 10^−12
Which statement about van der Waal interactions is false?
They are very strong
Consider the aquatic insects pictured in the accompanying figure. Which characteristic of water molecules directly contributes to their remarkable "water walking" success?
hydrogen bonds
The cohesiveness between water molecules is due largely to:
hydrogen bonds
A liquid with a pH of 7 is considered a(n) ____ solution.
neutral
The representation H−O−H is known as a(n):
structural formula
When a small amount of hydrochloric acid (HCl) is added to a solution of Na2HPO4, the pH of the solution does not change markedly. The pH also does not change drastically when a small amount of sodium hydroxide (NaOH) is added to this same solution. Based on these observations, the compound Na2HPO4 is:
acting as a buffer
Which of the following would most likely form electrolytes in water?
an inorganic compound
A chlorine atom has 17 protons and 18 neutrons. What is its atomic mass?
35 amu
Which component becomes oxidized in the following chemical reaction? 4 Fe + 3 O2 → 2 Fe2O3
iron
Which component is the oxidizing agent in the following chemical reaction?
oxygen
What type of bond is formed if one atom is more electronegative than the other atom?
polar covalent
A base is defined as a(n) _____ acceptor.
proton
Why can table salt (NaCl) dissolve easily in water?
The partial positive charge of the hydrogens in the water molecule can associate with the negative charge of the chloride ion, and the partial negative charge of the oxygen of the water molecule can associate with the positive charge of the sodium atom
What is the purpose of a buffer?
To minimize the change in pH
An atom X contains 14 protons, 13 electrons, and 12 neutrons, and atom Y contains 14 protons, 14 electrons, and 12 neutrons. What can you conclude?
X and Y are atoms of the same element
The covalent bond between a hydrogen atom and the oxygen atom in water is formed when:
hydrogen and oxygen share an electron pair
As water boils and turns to steam, what happens to the hydrogen bonds?
the hydrogen bonds break
Nitrogen has five electrons in its valence shell. How many electrons does it need to gain to complete its valence shell?
three
Which substance correctly identifies a reactant in the following chemical equation? CO2 + H2O ↔ H2CO3
water
