Answer:
c. 80 g
Explanation:
metal alloy:
- wt% = (mass compound/mass alloy)×100
for antimony:
⇒ 16% = (g antimony / g alloy)×100
⇒ 0.16 = g antimony / g alloy
∴ g alloy = 500 g
⇒ (0.16)×(500 g) = g antimony
⇒ g antimony = 80 g
We have two laws that cannot be violated. The conservation of mass and the conservation of energy.
The only reason why the beaker with the products has less mass than what you could expect is because part of the products are gases that escapes from the beaker.
Regarding the energy, the lower energy of the products is due to the release of heat during the chemical reaction.
1) The saturation point at 25°C is 35.7 g of NaCl / 100 g of water => 35.7 %
Under normal circumstances water will not accept more salt than that.
2) The solution with 1.55 mol of NaCl dissolved in 250 mL of water =>
molar mass of NaCl = 22.99 g/mol + 35.45 g/mol = 58.44 g/mol
grams of NaCl = 1.55 mol * (molar mass of NaCl) = 1.55mol * 58.44 g/mol = 90.58 grams of NaCl
grams of water = 250 mL * 1 g/mL = 250 g/g.
Concentration of the solution: [90.58 g NaCl / 250 g H2O] * 100 = 36.23 %
3) Conclusion: the solution has more salt than the saturation value. This means that the solution is supersaturated.
Supersaturation is a special condition, which is unstable, but that is not part of the questions.
The answer is supersaturated,
E) Steam and red hot iron