<span>The half-life of 9 months is 0.75 years.
2.0 years is 2.0/0.75 = 2.67 half-lives.
Each half-life represents a reduction in the amount remaining by a factor of two, so:
A(t)/A(0) = 2^(-t/h)
where A(t) = amount at time t
h = half-life in some unit
t = elapsed time in the same unit
A(t)/A(0) = 2^(-2.67) = 0.157
15.7% of the original amount will remain after 2.0 years.
This is pretty easy one to solve. I was happy doing it.</span>
A. Pyrite is an ore of gold and is used to jewelry making is a false statement
Answer:
46 g of sodium
Explanation:
Sodium reacts vigorously with fluoride gas to form NaF as shown
2Na (s) + F2 (g) ------> 2NaF (s) (Na = 23, F = 19)
2 moles of Na reacts with 1 mole of F2 to produce NaF
By calculating the molar mass of the elements involved in the reaction then multiplied by the mole, the mass can be obtained.
23 * 2 g/mol of Na reacts with 1 * 19 g/mol of F2
46 g/mol of Na reacts with 19 g/mol of F2 to produce NaF
Since the mole ratio is 2 to 1 and 19 g of F2 is used for the reaction, 46 g of sodium will be consumed for the reaction to be achieved.
