The answer is "<span>An atomic nucleus is positively charged because it is composed of protons". An atomic nucleus actually contains nucleons which are made up of both protons and neutrons. Since neutrons are neutral or have no charge, the charge of an atomic nucleus mainly relies on the positive charge of the protons.</span>
Answer:
d. Temperature and number of molecules of gas
Step-by-step explanation:
Boyle's Law states, "The volume of a fixed mass of a gas is inversely proportional to the pressure if the temperature remains constant."
Let's examine the words.
"… volume…is inversely proportional to the pressure …" This means that volume and pressure are the <em>variables</em>.
"… fixed mass of a gas …" means that the number of molecules is constant.
"… temperature remains constant" speaks for itself.
a, c, and e are <em>wrong</em>, because pressure is a variable.
b is <em>wrong</em>, because volume is a variable.
The change is called melting
Answer:
The correct answer is "Iron and oxygen act as Fe3+ and O2− ions respectively, forming rust (Fe₂O₃) in the presence of water by the formation of an ionic bond".
Explanation:
Rust is formed when iron reacts with oxygen in the presence of water (either if the iron is submerged or exposed to moisture in the air), forming the chemical compound Fe₂O₃. The presence of water is needed for rust formation because iron and oxygen act as ions when they are exposed to water, particularly Fe3+ and O2− ions respectively. The bond formed between these two elements are ionic bonds, because it is comprised of the reaction between a metal (iron) and a non-metal (oxygen).