A. is definitely true. The age of the plants and the amount of caffeine are two variables. The experimenter should have used only plants of the same age in order to determine the effect of caffeine.
b. is wrong. The amount of caffeine used was a variable.
c. is wrong. Temperature, water, and light were constants.
d. is wrong. The statement is a hypothesis that the experiment is trying to prove
Correct Answer: <span>They have small differences in electronegativity (statement 3)
Reason:
The nature of chemical bond between atoms is primarily driven by the electronegativity difference between constituent atoms. If electronegativity difference between constituent atoms is significantly higher, ionic bond formation is preferred. On other hand, low difference in electronegativity values, favours formation of covalent bond.
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Answer:
Atoms form chemical bonds to make their outer electron shells more stable. The type of chemical bond maximizes the stability of the atoms that form it. Covalent bonds form when sharing atoms results in the highest stability. Other types of bonds besides ionic and covalent chemical bonds exist, too.
Answer:
shiny
silvery-white
somewhat reactive metals at standard temperature and pressure
readily lose their two outermost electrons to form cations with a 2+ charge
low densities
low melting points
low boiling points
Explanation:
Answer: A chemical equilibrium exists when the rate at which reactants form products is the same as the rate at which products form reactants.
Explanation:
When the concentration of both the reactants and products do not change with time then it means the chemical reaction has reached to a state of chemical equilibrium.
For example, 
Therefore, we can conclude that a chemical equilibrium exists when the rate at which reactants form products is the same as the rate at which products form reactants.
