Answer:
Molality
Explanation:
The other answer has a very helpful explanation! I just confirm for others that this is correct on my test!
b) Calculate the amount of heat transferred when 3.55 g of Mg(s) reacts at constant pressure. delta H = -87.9 kJ
c) How many grams of MgO are produced during an enthalpy change of -238 kJ ? m = ?g
d) How many kilojoules of heat are absorbed when 40.5 g of MgO(s) is decomposed into Mg(s) and O2(g) at constant pressure? delta H =? kJ
Answer:
a. The reaction is exothermic.
b. -87,9 kJ
c. 9,60g of Mg(s)
d. 602kJ are absorbed
Explanation:
Based on the reaction:
2Mg(s) + O₂(g) → 2MgO(s) ΔH = -1204kJ
a. The reaction is exothermic. Because ΔH<0. That means the reaction produces heat when occurs
b. 3,55g of Mg(s) are:
3,55g Mg × ( 1mol / 24,305g) = 0,146 moles of Mg(s)
As 2 moles of Mg(s) produce -1204 kJ of heat:
0,146 moles of Mg(s) × ( -1204kJ / 2mol Mg) = -87,9 kJ
c. If -238 kJ of heat were transferred. The moles of Mg(s) that react must be:
-238kJ × ( 2mol Mg / -1204kJ) = 0,395 moles of Mg(s). In grams:
0,395 moles × ( 24,305g / 1mol Mg) = 9,60g of Mg(s)
d. The reverse reaction is:
2MgO(s) → 2Mg(s) + O₂(g) ΔH = +1204kJ
40,5g of MgO(s) are:
40,5g MgO × ( 1mol MgO / 40,3044g) = 1,00 moles of MgO(s)
As 2 moles of MgO absorbe 1204kJ of energy:
1,00 moles of MgO(s) × ( +1204 kJ / 2mol MgO) = 602kJ are absorbed
I hope it helps!
This response explains whether the reaction is exothermic or endothermic, calculates the amount of heat transferred in different scenarios, and determines the mass of MgO produced during a given enthalpy change. It also calculates the amount of heat absorbed during the decomposition of MgO.
a) This reaction is exothermic because the enthalpy change, represented by delta H, is a negative value (-1204 kJ).
b) To calculate the amount of heat transferred when 3.55 g of Mg(s) reacts, we can use the equation q = m * delta H. Plugging in the given values, we get q = (3.55 g) * (-87.9 kJ/1 mol) / (24.31 g/mol) = -15.98 kJ.
c) To determine the mass of MgO produced during an enthalpy change of -238 kJ, we can use the equation q = m * delta H and solve for m. Plugging in the given values, we get m = (-238 kJ) / (-1204 kJ/mol) * (40.31 g/mol) = 7.90 g.
d) To find the amount of heat absorbed when 40.5 g of MgO(s) is decomposed, we can again use the equation q = m * delta H. Plugging in the given values, we get q = (40.5 g) * (-1204 kJ/mol) / (40.31 g/mol) = -1209 kJ.
#SPJ3
A. Some ice cubes are floating in the tea
B. The sugar crystals are no longer visible in the tea
C. The mixture looks the same throughout
D. Some water droplets form on the outside of the glass
The subject is science
Answer:
The correct option is;
A. Some ice cubes are floating in the tea
Explanation:
A heterogenous mixture is one that is made up of more than one clearly identifiable phase of matter (such as solid and liquid, liquid and gas, gas and solid, or solid, liquid and gas combined) and therefore having non-uniform composition, which varies from one section to another within the mixture.
Ice cubes which are solids being observable on the surface of the mixture provides clue that the student has made an heterogenous mixture.
Answer:
22.4 L methane reacts with 44.8L of oxygen to give 44.8L of CO
2 and 22.4 L of water
Explanation:
From the balanced reaction: One mole(or 1 molecule or 16 g) of CH
4
reacts with 2 moles (or 2 molecules or 64 g) of oxygen to give one mole (or 1 molecule or 44 g) of CO
2
and 2 mole (or 2 molecules or 36 g) of water.
For the gaseous system at STP:
22.4 L methane reacts with 44.8 L of oxygen to give 22.4 L of CO
2
and 44.8 L of water.
and 2 mole (or 2 molecules or 36 g) of water.
For the gaseous system at STP:
22.4 L methane reacts with 44.8 L of oxygen to give 22.4 L of CO
2
and 44.8 L of water.