Iam chemistry is the worst and anything is appreciated!

2.78 mL of solution will be needed to make 4.5 M solution with 0.50 grams of NaOH.

Explanation:

Moles of sodium hydroxide = n

Volume of sodium hydroxide solution =V

Molarity of the sodium nitrate solution = 4.5 M

V  = 0.00278 L = 2.78 mL

2.78 mL of solution will be needed to make 4.5 M solution with 0.50 grams of NaOH.

answer: c. the experiment shows that the red substance experienced a chemical change.

explanation: chemical change is the change in which chemical composition of the substance changes. physical change is the change in which there is no change in chemical composition.

chemical changes are accompanied by following changes:

a) precipitate formation

b) energy is released or absorbed

c) formation of bubbles

d) change in color

as it is given that the red color has disappeared and there is production of gas, it means the red substance has undergone a chemical change.

e

nacl or sodium chloride is an ionic compound. this is because an ionic compound pertains to a compound that consists of positively and negatively charged ions. in this case, na (sodium) has a tendency to lose one electron when it reacts with with other atoms, so the resulting sodium ion contains 11 protons and 10 electrons, thus making it positively charged (na+), when chlorine reacts, it usually gains one electron to form an ion called chloride, thus making it negatively charged ( since the ions are oppositely charged, they attract.