Half life is defined as the amount of time it takes for a radioactive material to divide itself into half after radioactive decay process. So basically, after the prescribed half-life, what transforms to another material is 1/2 of the original and what is left is 1/2 as well. In this case, the formula applicable is
ln N/No = -kt
where N represents the masses before and after decay, t is the time elapsed and k is the decay rate constant.
Substituting,
ln 10/40 = -k*20
-k = <span>-0.0693
To find t1/2 or half life, then
ln 0.5 = -k*t1/2
t1/2 = ln 0.5 / 0.0693 = 0.1 minutes
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Answer:
The molarity is 6, 25M
Explanation:
A solution molar---> moles of solute ( in this case, magnesium oxide) in 1 L of solution :
0,8L solution-----5 moles solute
1 L solution----x=(1 L solutionx 5 moles solute)/0,8L solution= 6,25 moles solute---> 6,25M
<span>B, An Arrhenius acid donates H+ ions.</span>
Answer:
Mark me brainliest
Explanation:
Standards help avoid confusion and ambiguity when taking measurements. For example, a meter will always be the same length, no matter who is taking the measurement or where it is being taken.
Answer:
The answer to your question is: 83.9 %
Explanation:
Data
Cu = 31.8 g
S = 50 g
CuS = 40 g
yield = ?
Equation
Cu + S ⇒ CuS
MW Cu = 64 g
MW S = 32 g
MW CuS = 96 g
Ratio (theoretical/experimental)
Experimental 50/31.8 = 1.57
Theoretical 32/64 = 0.5 limiting reactant Cu
64 g of Cu ------------------ 96 g of CuS
31.8 g ------------------- x
x = (31.8 x 96) / 64
x = 47.7 g of CuS
% yield = (40/47.7) x 100
= 83.9 %