Answer:
3
Explanation:
A cyclic event is one that happens repeatedly.
The appearance of Hailey's Comet is a cyclic event because it has happened in various occasions in the past on a regular schedule as predicted. We have every reason to believe that the appearance of Hailey's Comet every 75 years will continue to be happen until the comet ceases to exist.
Answer: The weight/weight % or percent by mass of the solute is 5.41 %.
Explanation:
Mass of the sodium sulfate,w = 9.74 g
Volume of the water = 165 mL
Density of the water = 1 g/mL
Mass of the water =
Mass of the solution, W:
Mass of solute + Mass of solvent =9.47 g + 165 g=174.47 g
The weight/weight % or percent by mass of the solute is 5.41 %.
The balanced chemical reaction is written as:
4Al + 3O2 = 2Al2O3
To determine the mass of oxygen gas that would react with the given amount of aluminum metal, we use the initial amount and relate this amount to the ratio of the substances from the chemical reaction. We do as follows:
moles Al = 16.4 g ( 1 mol / 26.98 g ) = 0.61 mol Al
moles O2 = 0.61 mol Al ( 3 mol O2 / 4 mol Al ) = 0.46 mol O2
mass O2 = 0.46 mol O2 ( 32.0 g / mol ) = 14.59 g O2
Therefore, to completely react 16.4 grams of aluminum metal we need a minimum of 14.59 grams of oxygen gas.
Answer:
umm.. B. a base that generates a lot of hydroxide ions in water.
Answer:
-2092 kJ
Explanation:
Let's consider the chemical reaction that causes chromium to corrode in air.
4 Cr + 3 O₂ → 2 Cr₂O₃
We can calculate the standard Gibbs free energy (ΔG°) using the following expression.
ΔG° = ΔH° - T × ΔS°
where,
- ΔH°: standard enthalpy of the reaction
- ΔS°: standard entropy of the reaction
ΔG° = -2256 kJ - 298 K × (-0.5491 kJ/K)
ΔG° = -2092 kJ
