HESI Chemistry Practice Test 2
What is the most abundant element in Earth’s crust?
Εξήγηση:
Oxygen makes up about 47% of the Earth’s mass, followed by Silicon at 28%, Aluminum at 8%, Iron at 5%, Calcium at 4%, and Sodium and Potassium, each at 3%.
Viscosity increases in what circumstance?
Εξήγηση:
Viscosity, or the resistance of a fluid against force, increases with a temperature decrease, that is, fluid becomes more viscous (flows slower) in colder temperatures.
Which of the following statements about most metals is false?
Εξήγηση:
Metals are generally solids at ambient temperature, whereas nonmetals are usually gaseous.
What is the most abundant element in the universe?
Εξήγηση:
Hydrogen is the most abundant element in the universe, followed by Helium and then Oxygen.
The change in state from a gas to liquid is called what?
Εξήγηση:
Condensation is the reverse of vaporization and can be observed when gas cools and becomes a liquid, such as when dew appears in the morning after the temperature drops at night.
Which of the following is not a property of water?
Εξήγηση:
This is the only answer choice that is not true, as the question asks.
Which of the following elements does not appear on the periodic table?
Εξήγηση:
Because it is a combination of two elements, magnesium oxide does not appear on the periodic table.
A solution that contains the maximum amount of dissolved solute is said to be what?
Εξήγηση:
A saturated solution is one that has the maximum amount of solvent dissolved into it.
Lisa prepares soup by combining spices in a saucepan of boiling water and stirring until the spices are completely dissolved. She then adds a variety of diced veggies. What is the solute in her mixture?
Εξήγηση:
A solute is a material that dissolves when it comes into contact with another substance. The spices are the solute in this situation.
Which of the following would produce Hydrogen ions in an aqueous solution and would turn a litmus test from blue to red?
Εξήγηση:
Blue litmus paper turns red in the presence of an acid. Ammonia, lye, and detergent are basic, so they would not give off Hydrogen ions in an aqueous solution and when added to blue litmus paper the paper would remain blue.
Which of the following is true of gas particles?
Εξήγηση:
Gas particles exert little to no force on each other, so they “bounce” off each other when they collide. The other options are all false regarding gas particles.
Which one of the following elements is liquid at room temperature?
Εξήγηση:
Mercury is the only element that is liquid at room temperature.
All of the following factors influence the pace of a chemical reaction except?
Εξήγηση:
The pace of a chemical reaction is not affected by the quantity of mass lost since the law of conservation of mass (or matter) stipulates that there is no mass loss in a chemical reaction.
Reactions that absorb heat are called what?
Εξήγηση:
Endothermic reactions absorb heat, while exothermic reactions give off heat.
Using the Lewis-dot structure model, how many dots would carbon have?
Εξήγηση:
The number of dots in a Lewis-dot structure model corresponds to the number of valance electrons for that atom. Because carbon has four valance electrons, it’s Lewis-dot structure model would have 4 dots.
Dihydrogen monoxide is better known as what?
Εξήγηση:
Dihydrogen monoxide, or H2O, is more commonly known as water.