Answer:
126.5g
Explanation:
n=<u>m</u><u> </u>
M
where n is moles
m is mass of substance
M is molar mass
molar mass of sodium is 23g/mol
m=nM
m=5.5(23)
m=126.5
It would take 147 hours for 320 g of the sample to decay to 2.5 grams from the information provided.
Radioactivity refers to the decay of a nucleus leading to the spontaneous emission of radiation. The half life of a radioactive nucleus refers to the time required for the nucleus to decay to half of its initial amount.
Looking at the table, we can see that the initial mass of radioactive material present is 186 grams, within 21 hours, the radioactive substance decayed to half of its initial mass (93 g). Hence, the half life is 21 hours.
Using the formula;
k = 0.693/t1/2
k = 0.693/21 hours = 0.033 hr-1
Using;
N=Noe^-kt
N = mass of radioactive sample at time t
No = mass of radioactive sample initially present
k = decay constant
t = time taken
Substituting values;
2.5/320= e^- 0.033 t
0.0078 = e^- 0.033 t
ln (0.0078) = 0.033 t
t = ln (0.0078)/-0.033
t = 147 hours
Learn more: brainly.com/question/6111443
Answer:
212.304 grams
Explanation:
similar to your other question, use the same formula
q=mCpΔT
23617=m(4.182)(46.6-20)
23617=111.2412m
m=212.304g
The reaction is missing the Zn(s) in the reactants. The stoichiometry of the copper/zinc is 1 mole to 1 mole
Answer:
V = 81.14 L
Explanation:
Given data:
Volume of gas = ?
Number of moles = 3.30 mol
Temperature of gas = 25°C
Pressure of gas = 0.995 atm
Solution:
The given problem will be solve by using general gas equation,
PV = nRT
P= Pressure
V = volume
n = number of moles
R = general gas constant = 0.0821 atm.L/ mol.K
T = temperature in kelvin
Now we will convert the temperature.
25+273 = 298 K
now we will put the values in formula:
V = 3.30 mol 0.0821 atm.L/ mol.K 298 K / 0.995 atm
V = 80.74 L. atm / 0.995 atm
V = 81.14 L
