Answer:
a) The theoretical yield is 408.45g of 
b) Percent yield = 
Explanation:
1. First determine the numer of moles of 
and 
.
Molarity is expressed as:
M=
- For the
M=
Therefore there are 1.75 moles of
- For the
M=![\frac{2.0moles[tex]Na_{2}SO_{4}](https://tex.z-dn.net/?f=%5Cfrac%7B2.0moles%5Btex%5DNa_%7B2%7DSO_%7B4%7D)
}{1Lsolution}[/tex]
Therefore there are 2.0 moles of
2. Write the balanced chemical equation for the synthesis of the barium white pigment, :
3. Determine the limiting reagent.
To determine the limiting reagent divide the number of moles by the stoichiometric coefficient of each compound:
- For the :
- For the :
As the is the smalles quantity, this is the limiting reagent.
4. Calculate the mass in grams of the barium white pigment produced from the limiting reagent.
5. The percent yield for your synthesis of the barium white pigment will be calculated using the following equation:
Percent yield = 
Percent yield =
The real yield is the quantity of barium white pigment you obtained in the laboratory.
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:
15.Potassium oxide
16.Calcium chloride
17.Aluminium sulphide
18.CaS
Explanation:
15.K is the chemical symbol of Potassium and generally the name of the non-metal at the end of a formula has the suffix '-ide' and since O is oxygen, the name becomes Potassium oxide.
16. The same applies here. Ca is Calcium and Cl is Chlorine but since its the non-metal at the end, it ends in -ide. So Calcium chloride.
17.The same applies here too. Al is Aluminium and S is Sulphur so Aluminium sulphide.
18. Calcium's symbol is Ca and that of Sulphur is S and that gives the formula CaS.
For sig figs, you count the total number of numbers that aren’t 0, you only count 0 if they are after a decimal point. since there is not a decimal point, there are 2 significant figures, answer A
