this is a very hard question
It is so because warm air is lighter than cold air. Cold air means the molecules are not moving as much, so they will feel like sticking together and will not jump around as molecules in warm air will(higher temp. means higher KE). Think of a solid, colder solids are much heavier than warmer ones(think of ice-starts melting).
Answer:
We need 6.0 moles of aluminium
Explanation:
Step 1: Data given
Number of moles of H2 = 9.0 moles
Step 2: The balanced equation
2 Al + 6 HCl → 2 AlCl3 + 3H2
Step 3: Calculate moles Al
For 2 moles Aluminium, we need 6 moles HCl to produce 2 moles AlCl3 and 3 moles H2
For 9.0 moles of H2 we need 2/3 * 9.0 = 6.0 moles of aluminium
We need 6.0 moles of aluminium
The magnetic field is believed to be generated by electric currents in the conductive material of its core, created by convection currents due to heat escaping from the core. So your answer is A
