Answer:
Options B and C
Explanation:
Let's take a look at the options and get our answer by way of elimination. The basic definition of a neutral solution is given as;
A neutral solution is a substance which is neither acid nor basic . it has a PH of 7. it will have equal amount of H+ AND OH- ions in it.
a) a neutral solution does not contain any H3O+ or OH- This is wrong because take water as an example, it is neutral but contains both ions.
b) a neutral solution contains [H2O] = [H3O+]. This option is correct cause it is in line with the definition above.
c) an acidic solution has [H3O⁺] > [OH⁻]. Acidic solutions are any solution that has a higher concentration of hydrogen ions than water. This option is correct.
d) a basic solution does not contain any H3O⁺. This option is wrong. Basic solutions are any solution that has a higher concentration of hydroxide ions than water. This means they contain H3O⁺ but [OH⁻] is greater.
The answer is (2). Heat always flows down the temperature gradient, from high temperature to low temperature. Therefore, since the person is the warmest, heat flows from the person to both the ice and the air. Additionally, since the air is warmer than the ice, heat flows from the air to the ice.
Answer:
1) The power of Niagara Falls is 1.176 × 10⁹ W
2) The number of 15 W LED light bulbs it could power is 78.4 × 10⁶ light bulbs
Explanation:
1) The Niagara falls water mass flow rate = 2,400,000 kg/s
The height of the fall = 50 meters
The gravitational potential energy = Mass (kg) × height (m) × gravity (9.8 m/s²)
The power = The energy converted per second = Mass flow rate (kg/s) × height (m) × gravity (9.8 m/s²)
Therefore;
The power of Niagara Falls= 2,400,000 kg/s × 50 m ×9.8 m/s²= 1.176 × 10⁹ W
The power of Niagara Falls = 1.176 × 10⁹ W
2) The number, n, of 15 W LED light bulbs it could power is given by the relation;
n × 15 W = 1.176 × 10⁹ W
∴ n = 1.176 × 10⁹ W/(15 W) = 78.4 × 10⁶ light bulbs
The number of 15 W LED light bulbs it could power = 78.4 × 10⁶ light bulbs.
We determine the percent by mass of water in the compound by dividing the mass of water by the total mass. The total mass of Na2SO4.10H2O is equal to 322 g. The mass of water is 180 g.
percent by mass of water = (180 / 322)*(100 %) = 55.9%
