Chemistry Flashcards

All of the following factors influence the pace of a chemical reaction except?

Answer: Amount of mass lost

The pace or rate of a chemical reaction is influenced by factors such as the presence of catalysts, the surface area of reactants, and the temperature. The 'amount of mass lost' is not a factor influencing the reaction rate; rather, it would be a measurement of the extent of a reaction, and mass is conserved in chemical reactions.

Which of the following statements about most metals is false?

Answer: They are gases at room temperature

Most metals are known for properties like ductility, malleability, and being good conductors of heat and electricity. They constitute the majority of elements on the periodic table and are typically solid at room temperature, with mercury being a notable exception. Therefore, the statement that they are gases at room temperature is false.

Which of the following elements does not appear on the periodic table?

Answer: Magnesium oxide

The periodic table lists all known chemical elements. Chlorine, Bromine, and Phosphorous are all individual elements found on this table. Magnesium oxide (MgO), however, is a chemical compound formed from the elements Magnesium (Mg) and Oxygen (O), not an element itself, and thus does not appear on the periodic table.

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?

Answer: Spices

In a solution, the solute is the substance that gets dissolved, and the solvent is the substance that does the dissolving. In Lisa's soup, the spices are dissolved in the boiling water. Therefore, the spices are the solute in this mixture.

Using the Lewis-dot structure model, how many dots would carbon have?

Answer: 4

The Lewis-dot structure model represents an atom's valence electrons as dots around its symbol. Carbon is in Group 14 of the periodic table, meaning it has 4 valence electrons. Therefore, carbon would have 4 dots in its Lewis-dot structure.

Which of the following would produce Hydrogen ions in an aqueous solution and would turn a litmus test from blue to red?

Answer: Vinegar

Acids are substances that produce hydrogen ions (H+) when dissolved in an aqueous solution and turn blue litmus paper red. Vinegar contains acetic acid, which exhibits these properties. Ammonia, lye, and detergent are bases, which produce hydroxide ions (OH-) and turn red litmus blue.

Dihydrogen monoxide is better known as what?

Answer: Water

Dihydrogen monoxide is the systematic chemical name for the compound commonly known as water. The prefix 'di-' indicates two hydrogen atoms, and 'mono-' indicates one oxygen atom, corresponding to the chemical formula H2O.

What is the most abundant element in Earth’s crust?

Answer: Oxygen

Oxygen is the most abundant element found in Earth's crust. It is primarily present in various silicate minerals, which make up a significant portion of the crust's composition.

What is the most abundant element in the universe?

Answer: Hydrogen

Hydrogen is the most abundant element in the entire universe, making up approximately 75% of its baryonic mass. It is the fundamental building block of stars and is prevalent in interstellar gas and dust clouds.

Which one of the following elements is liquid at room temperature?

Answer: Mercury

Among the given options, Mercury (Hg) is the only element that is liquid at standard room temperature and pressure. Manganese, Magnesium, and Zinc are all solid metals under these conditions.

A solution that contains the maximum amount of dissolved solute is said to be what?

Answer: Saturated

A saturated solution contains the maximum amount of solute that can be dissolved in a given amount of solvent at a specific temperature. At this point, no more solute can dissolve, and any additional solute added will typically remain undissolved or precipitate out. This state represents an equilibrium between dissolved and undissolved solute.

The change in state from a gas to liquid is called what?

Answer: Condensation

Condensation is the process where a substance changes its physical state from a gas to a liquid. This occurs when gas particles lose enough thermal energy to slow down and come closer together, allowing intermolecular forces to pull them into a liquid form. A common example is water vapor turning into liquid water droplets, forming clouds or dew.

Which of the following is not a property of water?

Answer: Density of liquid form is less than solid form

The correct answer is that the density of liquid water is *greater* than its solid form (ice), which is an unusual property. Most substances become denser when they solidify. Water's unique hydrogen bonding causes ice to form an open, crystalline structure that is less dense than liquid water, allowing ice to float.

Viscosity increases in what circumstance?

Answer: Temperature decrease

Viscosity is a measure of a fluid's resistance to flow. When temperature decreases, the kinetic energy of the fluid's particles also decreases, causing them to move slower and experience stronger intermolecular forces. This increased resistance to movement among particles leads to an increase in the fluid's viscosity.

Which of the following is true of gas particles?

Answer: They exert little to no force on one another.

According to the kinetic molecular theory of gases, gas particles are in constant, random motion and are widely separated. They are considered to have negligible volume and exert very weak or negligible attractive or repulsive forces on one another. This allows them to move freely and independently within their container.

Reactions that absorb heat are called what?

Answer: Endothermic

Endothermic reactions are chemical processes that absorb heat energy from their surroundings. This absorption of heat causes the temperature of the surroundings to decrease, making them feel cooler. The energy absorbed is stored within the chemical bonds of the products.