Answer: C
Explanation:
In endothermic reactions, enthalpy is positive, and in exothermic reactions, enthalpy is negative, So, if enthalpy is positive, then it is an endothermic reaction, and hence is required for the reaction to occur.
The percent by mass sugar of a solution : 11.07%
<h3>Further explanation</h3>
Given
mass of sugar = 12.45 g
mass of water = 100 g
Required
The percent by mass
Solution
Mass of solution :

Percent mass of sugar :

Technically there is only one phase unless you account for a solution where you have a pure liquid with something dissolved in it. Unless you count aqueous as a phase which is just dissolved. Since you are in high school the answer you are looking for is one. <span />
Answer:
The volume is 13, 69 L
Explanation:
We use the formula PV=nRT. We convert the temperature in Celsius into Kelvin and the pressure in mmHg into atm.
0°C= 273K---> 56°C= 56 + 273= 329K
760 mmHg----1 atm
719 mmHg----x= (719 mmHgx 1 atm)/760 mmHg= 0,95 atm
PV=nRT ---> V= (nRT)/P
V=( 0,482 molx 0,082 l atm/K mol x 329K)/0,95 atm
<em>V=13,68778526 L</em>
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