unit 1
How is the work of scientists checked for accuracy?
Scientists submit their work to scientific journals, and it is reviewed by their peers.
Molten lava coming out of a Hawaiian volcano cools down and forms rock.
Which statement best describes the flow of energy in this scenario?
Energy moves from the lava to the surroundings.
Which of the listed properties is the same for the elements beryllium (Be), magnesium (Mg), and calcium (Ca)?
number of valence electrons
What defines endothermic reactions and exothermic reactions?
Select all that apply.
Exothermic reactions are chemical reactions that release energy into the surrounding environment.
Endothermic reactions are chemical reactions that absorb energy from the surrounding environment.
A soda factory dissolves carbon dioxide (CO2) into water (H2O) as part of its manufacturing process.
Which option categorizes the solution the soda factory is creating?
gas-liquid
Which option most likely describes scientist(s) working in pure science?
Two scientists in a lab examining vials of urine they are analyzing for levels of excreted protein.
Boiling water on a heated stove begins to evaporate into a gas.
Which statement best predicts what will happen to the temperature as the water evaporates?
The temperature will not change.
If the following elements were involved in a chemical reaction, which one would be most likely to form a cation?
potassium (K)
Which of the answer choices correctly describes Le Châtlier's principle?
When a reaction is at chemical equilibrium, a change in the system will cause the system to shift in the direction that will balance the change and help the reaction regain chemical equilibrium
What is the role of the kinetic theory of matter in the process of solutes being dissolved into solvents?
The continuous motion of the particles in the solvent and solute cause them to collide with one another, which results in bonds being broken, attractions being disrupted, and particles being separated from one another.
Which best explains what happens when scientific theories do not stand up to repeated experimentation?
The theories change to fit current data.
Which answer choice best describes John Dalton's contribution to atomic theory?
He gave future scientists a foundation for understanding how atoms make up matter.
Which statement correctly describes a covalent bond?
The valence electrons are shared between the atoms
Examine the reversible reaction among gases.
3H2 + N2 ⇌⇌ 2NH3
If pressure were added to this reaction when it is at chemical equilibrium, what would occur?
The reaction rate of the forward reaction would increase in order to decrease the number of particles
What option defines solute?
the substance in a solution that has been dissolved
Scientists have increased their ability to make observations beyond their own senses through the invention of specialized equipment such as Xray telescopes.
Which best explains how such technology has affected society?
Human knowledge of the universe beyond Earth has increased.
individual : identification card :: element : _[blank]_
Which answer choice best completes the analogy?
atomic fingerprint
Why does the reactivity of elements increase moving left to right on the periodic table?
Atoms of elements are closer to filling their valence shell with electrons.
What explains how the law of conservation of energy is fulfilled during an exothermic reaction?
In an exothermic reaction, the products have less potential energy than the reactants, so energy is released into the surroundings during the reaction.
Which option describes ionic solutes?
Ionic solutes consist of oppositely charged ions that are attracted to each other, and these solutes can be dissolved through dissociation.
Which best describes how scientists behave when the results of an experiment do not support a theory?
Scientists conduct further experiments.
A scientist discovers that an atom with a mass number of 14 contains eight electrons.
According to this scenario, what is the atom's atomic number?
8
potassium (K)
magnesium (Mg)
helium (He)
fluorine (F)
Which answer choice lists the elements in order from the smallest atomic radius to the largest atomic radius?
helium, fluorine, magnesium, potassium
Examine the scenario.
Chemical Reaction A and Chemical Reaction B involve the same two reactants. Chemical Reaction A is performed in a hot container, while Chemical Reaction B is performed in a cold container.
Which of the answer choices correctly describes which chemical reaction will have a higher reaction rate?
Chemical Reaction A will have a higher reaction rate, because its container has more thermal energy. This thermal energy will cause an increase in the motion and collisions of the reactants' particles.
What is an example of dissociation?
table salt dissolving in water