Answer:
C. Endothermic
Explanation:
Since the products potential energy is higher than the reactants potential energy, it has abosrbed energy, thus making the graph endothermic.
Combining the two clear colorless liquids is a chemical change because a different solid substance is formed. Tell students that a precipitate is an insoluble solid that forms when two solutions are combined and react chemically.
Answer : The percent-by-mass concentration of acetic acid is, 5.15 %
Explanation : Given,
Mass of acetic acid = 51.80 g
Density of solution = 1.005 g/ml
Volume of solution = 1.000 L = 1000 ml (1 L = 1000 ml)
First we have to calculate the mass of solution.


Now we have to calculate the percent-by-mass concentration of acetic acid.

Now put all the given values in this formula, we get:

Therefore, the percent-by-mass concentration of acetic acid is, 5.15 %
The given question is incomplete. The complete question is:
The change in entropy is related to the change in the number of moles of gas molecules. Determine the change in moles of gas for each of the reactions and decide if the entropy increases decreases or has little to no change:
A. 
B. 
C. 
D.
Answer: A.
: decreases
B.
: decreases
C.
: no change
D.
: increases
Explanation:
Entropy is defined as the randomness of the system.
Entropy is said to increase when the randomness of the system increase, is said to decrease when the randomness of the system decrease and is said to have no change when the randomness remains same.
In reaction
, as gaseous reactant is changed to solid product, entropy decreases.
In reaction
, as 4 moles of gaseous reactants is changed to 2 moles of gaseous product, entropy decreases.
In reaction
, as 3 moles of gaseous reactants is changed to 3 moles of gaseous product, entropy has no change.
In reaction
, as 1 mole of gaseous reactant is changed to 3 moles of gaseous product, entropy increases.