15mL because if it started as 20 mL and went to 35mL when u put in pyrite, the pyrite takes up 15mL
3Ba + N2 -----> Ba3N2
Ba is in the second group and metal, its charge = +2 in the compound.
N is non-metal, it is in 15th group, so it has 5 electrons on the last level, so it can take 3 electrons more(8-5=3). N has charge (-3) in compound.
Ba and N form compound Ba3N2.
Answer:
28g remain after 13.5 hours
Explanation:
Element decayment follows first order kinetics law:
ln[Pa-234] = -kt + ln [Pa-234]₀ <em>(1)</em>
<em>Where [Pa-234] is concentration after t time, k is rate constant in time, and [Pa-234]₀ is initial concentration</em>
Half-life formula is:

6.75 = ln2 / k
<em>k = 0.1027hours⁻¹</em>
Using rate constant in (1):
ln[Pa-234] = -0.1027hours⁻¹×13.5hours + ln [112.0g]
ln[Pa-234] = 3.332
[Pa-234] = <em>28g after 13.5 hours</em>
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12➡6➡3➡1.5
① ② ③
3 half life = 252
half life = 84days