The number of half -lives that has passed after 105 hours for krypton-79 that has half-life of 35 hours is calculated as below
if 1 half life = 35 hours
what about 105 hours = ? half-lives
= (1 half life x105 hours) /35 hours = 3 half-lives has passed after 105 hours
There are 50.9415 grams in vanadium
hope that helps :)
Because of its chemical structure.
Answer:
Write a balanced chemical reaction:
N2 + 3H2 ==> 2NH3
Looking at the mole ratios in this balanced equation you can see it takes 3 moles H2 to make 2 moles NH3. So, next calculate the moles of NH3 represented by 1.80 g and then convert to moles of H2 needed:
moles of NH3 = 1.80 g x 1 mole/17 g = 0.106 moles NH3
Moles H2 needed = 0.106 moles NH3 x 3 moles H2/2 moles NH3 = 0.159 moles H2 needed
Grams H2 needed = 0.159 moles x 2 g/mole = 0.318 grams H2 needed
Explanation:
