Answer:
The ones with 8 protons
Explanation:
Since there are two of them with 8 protons, we can assume they are the same element. The first 8 proton element has 10 neutrons while the second has 11. This makes them isotopes of one another
First M stands for Molarity which is (moles of solute) / (Liters of solution). we also know that moles = (mass) / (molar mass). so we can form some equations here. We know:
Molarity (M) = moles (mol) / Liters (L)
moles (mol) = (mass) / (molar mass)
we can substitute the (mass) / (molar mass) for (moles) and get:
M = [(mass) / (molar mass)] / Liters
we can now isolate mass and get
M * Liters * molar mass = mass
now we need to find the molar mass of CaCl2 which is 110.98 g/mol
plug the values in and get
.350M * 6.5L * 110.98 g/mol = mass
mass = 252.4795g however the 6.5L has only 2 sig figs so i would say
mass CaCl2 = 2.5 * 10 ^2 g
The balanced chemical reaction is:
<span>2H2O= 2H2 + O2
</span>
We are given the amount of oxygen to be produced in the reaction. The starting point for the calculations will be this amount.
50 g ( 1 mol O2 / 32 g O2 ) ( 2 mol H2O / 1 mol O2 ) ( 18.01 g H2O / 1 mol H2O) = 56.28 g of H2O is needed.
Therefore, the correct answer is the last option.
To make sure no cracks are in the crucible and also to remove any moisture present in the crucible by the process of heating.
