Answer:
Q = -3980.9 j
Explanation:
Given data:
Mass of sample = 30 g
Initial temperature = 56.7 °C
Final temperature = 25 °C
Specific heat of water = 4.186 j/g.°C
Amount of heat released = ?
Formula:
Q = m.c.ΔT
Q = heat released
m = mass of sample
c = specific heat of given sample
ΔT = change in temperature
Solution:
ΔT = T2 -T1
ΔT = 25 °C - 56.7 °C = - 31.7°C
Q = m.c.ΔT
Q = 30 g × 4.186 j/g.°C × - 31.7°C
Q = -3980.9 j
Answer:
Solid particles have the least amount of energy, and gas particles have the greatest amount of energy. The temperature of a substance is a measure of the average kinetic energy of the particles. A change in phase may occur when the energy of the particles is changed.
Explanation:
Solid particles have the least amount of energy, and gas particles have the greatest amount of energy. The temperature of a substance is a measure of the average kinetic energy of the particles. A change in phase may occur when the energy of the particles is changed.
Answer:
Explanation:
The mass percentages of chlorine and fluorine:
Given:
Mass of chlorine = 5.753g
Mass of fluorine = 9.248g
Find the total of the masses given:
Total mass = mass of chlorine + mass of fluorine = 5.753 + 9.248 = 15.001g
% of Cl = 
x 100
% of Cl = 
x 100 = 38.35%
% of F = 
x 100
% of F = 
x 100 = 61.65%
Answer:
0.04 mol
Explanation:
Given data:
Mass of barium = 5.96 g
Moles of barium = ?
Solution:
Formula:
Number of moles = mass/molar mass
Molar mass of barium = 5.96 g/ 137.33 g/mol
Number of moles = 0.04 mol
Thus the number of moles of barium in 5.96 g are 0.04 moles. The chemist weight out the 0.04 moles .
We have the following balanced equation:
They also give us the heat of reaction equal to -764 kJ, i.e. it is an exothermic reaction.
By observing the reaction, we can deduce that for this heat to be generated, one mole of methanol is needed. Now let's see how many grams that mole of methanol equals. We will use the molecular weight equal to 32.04 g/mol
Now we know the grams of methanol that generate 764 kJ, because the heat of reaction is directly proportional to the mass of the reactants, we can apply a rule of three to know the grams needed to produce a heat of reaction equal to 701 kJ:
So, 29.4 g of methanol must be found to produce 701 kJ of heat
