A) physical
B) chemical
C) chemical
D) physical
E) physical
Answer:
A is the answer. Chemical changes happen when atomic bonds are broken or created during chemical reactions. Hence, in this case, it involve changes to molecular structure.
- Change in states are physical changes.
- When salts are dissolved in water, you can use Distillation to separate them. Distillation is a physical change as well.
- Dissolving is just physical change.
Explanation:
The statement that is true of a chemical change among the statements given in the question is "It involves changes in the molecular structure". The correct option among all the options that are given in the question is the first option or option "A". I hope the answer has actually come to your help.
When magnesium is burned, it reacts with oxygen in air not with the fire. The fire is the energy needed for the reaction to happen. Magnesium reacts with oxygen forming magnesium oxide. The light emitted from the reaction is because the reaction produced a lot of heat.
Answer: Thus 663 J of heat is released when 27.6 g
cools from 83.1 °C to 55.6 °C
Explanation:
The quantity of heat required to raise the temperature of a substance by one degree Celsius is called the specific heat capacity.

Q = Heat released = ?
m = mass of substance = 27.6 g
C = specific heat capacity = 
Initial temperature=
= 
Final temperature =
= 
Change in temperature ,
Putting in the values, we get:

As the value of q is negative, it means the heat has been released and it is 663J