What is Molarity ?
Molarity (M) is defined as the number of moles of solute dissolved in 1L of solution. Molarity is also known as Molar concentration. The S.I unit of Molarity is molar (M) or mol/L.
The conversion sequence is
mL solution → L solution → mol → g
= 0.5376 g
Answer:
1s2, 2s2, 2p6, 3s2, 3p2
Explanation:
see the guide on the given electron configuration examples
7. A (Lower numbered levels are closer to the nucleus) (n=1 is the closest that an electron can get to the nucleus) (Decreasing levels = releasing energy) (Increasing levels = gaining energy) (The greater the change in distance, the greater the release/gain of energy)
8. C
9. A
10. B (Think of somebody jumping. They are on the ground and they can jump upwards, but they cannot jump further down. This is the lowest place they can be)
11. B (When an atom emits light, it is emitting energy. This means that an electron will have to drop down a level (or multiple levels) because it doesn't have enough energy to stay on the higher levels)
12. C
Answer: Steel wool turns from a gray color to a reddish color after it gets wet and then sits on a counter is a sign of chemical change.
Explanation:
A change that brings change in chemical composition of a substance is called a chemical change.
For example, Steel wool turns from a gray color to a reddish color after it gets wet and then sits on a counter is a chemical change.
This is because steel wool is mostly made up of iron and when iron becomes wet then in the presence of air it gets oxidized and therefore, it gets corroded.
This corrosion appears as reddish color of steel wool and it represents a chemical change has occurred in the steel wool.
Thus, we can conclude that steel wool turns from a gray color to a reddish color after it gets wet and then sits on a counter is a sign of chemical change.
Answer:
ΔU = - 168 KJ
Explanation:
- ΔU = Q + W.....................first law
∴ W = - 61 KJ........A system performs on its surroundings
∴ Q = - 107 KJ,,,,,,A system release heat
⇒ ΔU = - 107 KJ - 61 KJ = - 168 KJ