Answer:
true mass is based on gravity
The answer is B because isotopes have the same number of protons and neutrons.
Examination by a test; experiment, as in chemistry, metallurgy, etc.
Answer:
Endothermic
It absorbs heat
1.20 × 10³ kJ
Explanation:
Let's consider the following thermochemical equation.
2 H₂O(l) → 2 H₂(g) + O₂(g) ΔH = 572 kJ
Since ΔH > 0, the reaction is endothermic, that is, it absorbs heat when H₂O reacts.
572 kJ are absorbed when 36.03 g of water react. The heat absorbed when 75.8 g of H₂O react is:
75.8 g H₂O × (572 kJ/36.03 g H₂O) = 1.20 × 10³ kJ
Answer:
a) Unsaturated
b) Supersaturated
c) Unsaturated
Explanation:
A saturated solution contains the <u>maximum amount of a solute that will dissolve in a given solvent at a specific temperature</u>.
An unsaturated solution contains <u>less solute than it has the capacity to dissolve. </u>
A supersaturated solution, <u>contains more solute than is present in a saturated solution</u>. Supersaturated solutions are not very stable. In time, some of the solute will come out of a supersaturated solution as crystals.
According to these definitions and considering that the solubility of KCl in 100 mL of H₂O at <u>20 °C is 34 g</u>, and at <u>50 °C is 43 g</u> we can label the solutions:
a) 30 g in 100 mL of H₂O at 20 °C ⇒ unsaturated
b) 65 g in 100 mL of H₂O at 50 °C ⇒ supersaturated
c) 42 g in 100 mL of H₂O at 50 °C and slowly cooling to 20 °C to give a clear solution <u>with no precipitate</u> ⇒ unsaturated (if it were saturated it would have had precipitate)
