Explanation:
Using stratified random sampling, researchers must identify characteristics, divide the population into strata, and proportionally choose individuals for the representative sample. ... For example, individuals who are too busy to participate will be under-represented in the representative sample.
Answer:
d. 12.3 grams of Al2O3
Explanation:
Based on the reaction:
4Al + 3O2 → 2Al2O3
<em>Where 4 moles of Al reacts in excess of oxygen to produce 2 moles of aluminium oxide.</em>
<em />
To solve this question we must find the moles of Aluminium. With these moles we can find the moles of aluminium oxide using the reaction:
<em>Moles Al -Molar mass: 26.9815g/mol-</em>
6.50g * (1mol / 26.9815g) = 0.241 moles Al
<em>Mass Al₂O₃ -Molar mass: 101.96g/mol-</em>
0.241 moles Al * (2 mol Al2O3 / 4 mol Al) = 0.120 moles Al2O3
0.120 moles Al2O3 * (101.96g / mol) =
12.3g of Al2O3 are produced.
Right answer is:
<h3>d. 12.3 grams of Al2O3
</h3>
Answer: Anna stated that ionic compounds have high melting point and low boiling point. The error in the statement is that ionic compound have low boiling point, instead ionic compounds have high boiling point, because in an ionic compound, the force of attraction working between two ions is very strong and hence the bonds present are very strong, and a lot of energy is needed to break them
Answer:
8L
Explanation:
Using Boyle's law which states that the volume of a given mass of gas is inversely proportional to the pressure, provided temperature remains constant
P1V1= P2V2
P1 = 2atm, V1 = 12L ,
P2 = 3atm , V2 =
12 × 2 = V2 × 3
Divide both sides by 3
V2 = 24 ÷ 3
V2 = 8L
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Given:
35.0 mL of acid with an unknown concentration
24.6 mL of 0.432 M base
Required:
Concentration of the acid
Solution:
M1V1 = M2V2
M1 (35.0 mL of acid)
= (0.432 M base) (24.6 mL
of base)
V1 = (0.432
M base) (24.6 mL of base) /
(35.0 mL of acid)
M1 = 0.304 M of acid
