Fe3O4 + 4H2 = 3Fe + 4H2O
Fe3O4 + 4H2SO4 = Fe2(SO4)3 + FeSO4 + 4H2O
Answer:
A) NE
Explanation:
I'm no genius but I believe this is correct.
We are given the balanced equation 2NaF + Ca10(PO4)6(OH)2 → Ca10(PO4)6F2 + 2NaOH. The fluorapatite is the product together with sodium hydroxide. The ions involved are (PO4) 3-, Ca 2+ and <span>F-. We add the charges and check if the sum is zero, 2*10+-3*6+-1*2 =0. the zero sum tells that the compound has zero charge or neutral</span>
The answer is 6×10⁹ years.
K-Ar dating is radioactive dating method used to measure a time elapsed since the rock is cool enough to trap Ar after a radioactive decay of 40K to 40Ar. It can be expressed as:
where:
- elapsed time
- half-life of K40
- amount of K40
<span>
- amount of Ar40
</span>
We know that a half-life of K40 is 1.251<span>×10⁹ years:
</span>
We do not know absolute value of amount of K40 and Ar40, but we know percentage and can express them as following:
<span>
</span>
So:
⇒ t = <span>6×10⁹
</span>
Thus, the rock is old <span>6×10⁹ years.</span>
Answer:
61.5 dry quarts = 67.72509L
Explanation: