I think d is wrong because Everything else is correct for sure. also, minerals vary in the position they hold and have different chemical compounds.
Answer: A/40 it is actually 39.997 but since that is not an answer they rounded up
Explanation:
Answer: 0.9375 g
Explanation:
To calculate the number of moles for given molarity, we use the equation:
.....(1)
Molarity of 
solution = 0.75 M
Volume of solution = 25.0 mL = 0.025 L
Putting values in equation 1, we get:
According to stoichiometry :
2 moles of require = 1 mole of 
Thus 0.01875 moles of will require=
of
Mass of 
Thus 0.9375 g of is required to react with 25.0 ml of 0.75 M HCl
Missing question: Z:X = 7:1 A:Z = 2.5:1 A:Z = 2.2:1 Y:X = 11:1.
Answer is:<span> Z:X = 7:1 and Y:X = 11:1.
Law of multiple proportions or Dalton's Law
said that the ratios of the masses of the second element which
combine with a fixed mass of the first element will be ratios of small whole
numbers.
In this example ratios are whole numbers, A:Z = 2.5 : 1
and A:Z = 2.2 : 1 are not whole number ratios.</span>
