The given question is incomplete. The complete question is as follows.
Which of the following best helps explain why an increase in temperature increases the rate of a chemical reaction?
(a) at higher temperatures, high-energy collisions happen less frequently.
(b) at low temperatures, low-energy collisions happen more frequently.
(c) at higher temperatures, less-energy collisions happen less frequently.
(d) at higher temperatures, high-energy collisions happen more frequently
Explanation:
When we increase the temperature of a chemical reaction then molecules of the reactant species tend to gain kinetic energy. As a result, they come into motion which leads to more number of collisions within the molecules.
Therefore, chemical reaction will take less amount of time in order to reach its end point. This means that there will occur an increase in rate of reaction.
Thus, we can conclude that the statement at higher temperatures, high-energy collisions happen more frequently, best explains why an increase in temperature increases the rate of a chemical reaction.
a metal with a large number of free-flowing electrons most likely have good conductivity
Answer:
The nuclear charge increases, but the number of inner shielding electrons stays the same.
Explanation:
Their shielding does not change, so the effective nuclear charge — the charge felt by a valence electron — increases.
The valence electrons are pulled closer to the nucleus, decreasing the atomic radius.
For example, consider the elements of Period 3.

The number of protons increases as you go from one element to the next, but the number of inner electrons is constant.
Explanation:
A 57.9 g sample of glass is cooled by 2.70'C how much heat does it release
1560
Answer:
56160grams
Explanation:
First, we need to convert the number of molecules of magnesium chloride (MgCl2) into moles by dividing by Avagadro's number (6.02 × 10^23 molecules)
n = nA ÷ 6.02 × 10^23
n = 14.07 × 10^26 ÷ 6.02 × 10^23
n = 14.07/6.02 × 10^(26-23)
n = 2.34 × 10^3 moles of MgCl2
The balanced reaction given in the question is as follows:
Mg + 2HCl → MgCl2 + H2
If 1 mole of Mg produced 1 mole of MgCl2
Then, 2.34 × 10^3 moles of Mg will also produce 2.34 × 10^3 moles of MgCl2.
Using mole = mass ÷ molar mass (MM)
Molar mass of Mg = 24g/mol
mass = mole × MM
mass = 2.34 × 10^3 × 24
mass = 56.16 × 10^3
mass = 56160grams.