Answer:
It changed by -7 degrees Celsius.
Explanation:
First a balanced reaction equation must be established:

→

Now if mass of aluminum = 145 g
the moles of aluminum = (MASS) ÷ (MOLAR MASS) = 145 g ÷ 30 g/mol
= 4.83 mols
Now the mole ratio of Al : O₂ based on the equation is 4 : 3
[
4Al +
3 O₂ → 2 Al₂O₃]
∴ if moles of Al = 4.83 moles
then moles of O₂ = (4.83 mol ÷ 4) × 3
=
3.63 mol (to 2 sig. fig.)
Thus it can be concluded that
3.63 moles of oxygen is needed to react completely with 145 g of aluminum.
Answer:
B
Explanation:
If you are comparing an amount you are trying to find the quantity or the total of something or the size therefore answer B is the right answer
At a definite amount of solute and at a definite tempreture it is dissolved in utane above that it remain unsoluble
Its 3, because you cant filter out or evaporate an element from a compound, for example water mixed with sand is a ''mixture and the sand can be filtered out, or water with dissolved sugar is also a 'mixture' and the water can be evaporated.