Recorded observations is called data.
Answer:
ºC
Explanation:
We have to start with the variables of the problem:
Mass of water = 60 g
Mass of gold = 13.5 g
Initial temperature of water= 19 ºC
Final temperature of water= 20 ºC
<u>Initial temperature of gold= Unknow</u>
Final temperature of gold= 20 ºC
Specific heat of gold = 0.13J/gºC
Specific heat of water = 4.186 J/g°C
Now if we remember the <u>heat equation</u>:


We can relate these equations if we take into account that <u>all heat of gold is transfer to the water</u>, so:

Now we can <u>put the values into the equation</u>:

Now we can <u>solve for the initial temperature of gold</u>, so:

ºC
I hope it helps!
I think its a hydrogen bonding
Answer:
Both are equal
Explanation:
Mass of starting material i.e Aluminium is
grams
The weight of oxygen is 
There are 4 atoms of aluminium and 3 atoms of oxygen
Thus, the total mass of starting material is
mass of one atom of aluminium
mass of one atom of oxygen

grams
Mass of new substance is also equal to
mass of one atom of aluminium
mass of one atom of oxygen

grams