Since it's Li+1, that means it's a Lithium ion, not just the element itself. The +1 charge means it loses an electron. The dot structure would be Lithium, and however many valence electrons it has minus 1
For a first order reaction, the half life is inversely proportional to the rate constant.
The formula is
half life = ln(2)/k = 0.693/k
where k is the rate constant
t = 5.50 minutes
k = ln(2)/5.50 = 0.126 min^-1
Your rate constant is 0.126 min^-1.
Hi I'm in Chemistry too this year,
I believe D is correct because usually physical changes are things like density, color or quantity.
M = n/V
.5M = n/.100 L
n = .1 L * .5M
n= .05 mols of MgCl2
mass of MgCl2 = .05 mols of MgCl2 * 95.211 grams/ 1 mol of MgCl2
mass of MgCl2 = 4.76 grams
4.76 grams of MgCl2 is needed to make 100 ml of a solution that is .500M, in chloride ion. Bolded = confused
The answer is the 3rd one down I think
