Answer:
Explanation:
Aluminium is used in rechargeable battery.
Aluminium ions provide the energy by flowing from anode to the cathode.
When the battery is recharged these ions comes to the anode.
The one ion gives three electrons. Which means one Al⁺³ is equal to the three Li⁺ ions. So, three unit of charge giving by ions increase the energy storage capacity.
The rechargeable batteries with aluminium gives low cost and low flammability.
It is safe to use because of inertness of aluminium and also easy to use in ambient environment.
Aluminium also have high volume capacity than lithium which means energy storage per volume is greater.
Its charge discharge cycles are also greater.
The aluminum ion batteries are also smaller in size.
The 2nd energy level can hold a maximum of 8 electrons.
The number is written in scientific notation.
The significant figures are the numbers known precisely plus 1 digit that is uncertain.
When the numbers are expressed in scientific notation all the digits before 10^n are significant.
So, 7 and 8 are significant figures and the answer is that the number of significant figures is 2.
Answer: 2
The piece of unknown metal is in thermal equilibrium with water such that Q of metal is equal to Q of the water. We write this equality as follows:
-Qm = Qw
Mass of metal (Cm)(ΔT) = Mass of water (Cw) (ΔT)
where C is the specific heat capacities of the materials.
We calculate as follows:
-(Mass of metal (Cm)(ΔT)) = Mass of water (Cw) (ΔT)
-68.6 (Cm)(52.1 - 100) = 42 (4.184) (52.1 - 20)
Cm = 1.717 -----> OPTION C
