Answer:
A compound contains atoms of different elements chemically combined together in a fixed ratio. An element is a pure chemical substance made of same type of atom. Compounds contain different elements in a fixed ratio arranged in a defined manner through chemical bonds. They contain only one type of molecule.
Answer:
Many areas of the United States experience explosive population growth. <u>The more people that reside someplace, the more demand there is for water there.</u> Often these urban-growth <u>expansions are unplanned and place extraordinary stress on the water supply system, mainly on the groundwater.</u> <u>The stress often depletes groundwater supply, thereby causing wells to dry up.</u> Then water must be brought from somewhere else to support the local population.
Such situations have occurred all over the United States. For example, increased population growth in the southwestern United States has significantly lowered the water table 50 to 200 feet (depending on the area) since the 1940s. Managing urban growth, efforts to reduce water demand, conservation of the resource, and attempts to increase the water supply all address the problem of exceeding water resource limits.
<u>Human activities affect groundwater quality.</u>
<u>Here are some sources </u>and possible solutions to groundwater pollution:
<u>Agriculture</u>—Reduce usage of pesticides and fertilizers.
<u>Landfills</u>—Monitor for leakage and repair linings.
<u>Underground storage tanks</u>—Remove damaged and unused tanks.
<u>Household wastes</u>—Properly dispose of household hazardous waste.
<u>Septic tank leaks</u>—Properly maintain and repair tanks.
Explanation:
This came from the K12 learning course read this and the answer will be there. I underlined the important parts for the answer.
Answer: An ionic bond is a type of chemical bond formed through an electrostatic attraction between two oppositely charged ions. Ionic bonds are formed between a cation, which is usually a metal, and an anion, which is usually a nonmetal.
basically explains
<u>Answer:</u> The net ionic equation for the given reaction is 
<u>Explanation:</u>
Net ionic equation of any reaction does not include any spectator ions.
Spectator ions are the ions which do not get involved in a chemical equation. It is also defined as the ions that are found on both the sides of the chemical reaction when it is present in ionic form.
The chemical equation for the reaction of hydrochloric acid and potassium sulfite is given as:

Ionic form of the above equation follows:

As, potassium and chloride ions are present on both the sides of the reaction, thus, it will not be present in the net ionic equation.
The net ionic equation for the above reaction follows:

Hence, the net ionic equation for the given reaction is written above.
Answer:
1,2,3
Explanation:
Heat gain implies that heat is absorbed by the system in order to make the stated phase transition possible.
Before a liquid changes to gas, intermolecular forces in the liquid are broken by energy supplied as heat.
Also, transition from solid to liquid requires energy to break intermolecular bonds.
Finally, sublimation requires input of energy in the form of heat.