Answer:
a: chemical change because the change cannot be reversed.
b: physical change because the action can be reversed.
c: chemical change.
d:chemical change.
any change that cannot be reversed is a chemical change and any change that can be reversed is a physical change.
Answer : The heat your body transfer must be, 25.1 kJ
Explanation :
Formula used :
or,
where,
Q = heat = ?
m = mass of water = 500.0 g
c = specific heat of water = 
= initial temperature = 
= final temperature = 
Now put all the given value in the above formula, we get:
Therefore, the heat your body transfer must be, 25.1 kJ
I'm not sure, but maybe burning point...
Answer : The Bronsted-Lowry theory was not against the Arrhenius theory, rather it was just a modification to the previous theory of acids and bases. Hydroxide ions are considered as bases because they have the tendency to accept hydrogen ions from acids and form water.
An acid was the one which produces hydrogen ions in solution because it reacts with the water molecules by giving a proton to them.
In a nutshell, he described bases as hydrogen acceptor and acids as hydrogen donors.
