Answer:
A. -163.96kJ
B. -158.34kJ
Explanation:
Heat of combustion is the heat released when an element with oxygen at stp.
Reaction for the combustion of carbon:
C(s) + O2(g) --> CO2(g)
Enthalpy heat of combustion, C (using Hess law) = -393.5 kJ/mol
m = 5g
Molecular weight = 12 g/mol
No of moles = mass/molecular weight
= 5/12
= 0.417mol
DH = -393.5 * 0.417
= -163.96 kJ
B. Heat absorbed by the calorimeter = heat evolve by combustion
= mCH2ODT + mCcDT
Where CH2O is the specific heat capacity of the water in the calorimeter
Cc is the specific heat capacity of copper calorimeter
= (2500*4.184*14.1) + (2000*0.385*14.1)
= -158343J
= -158.34kJ
The mass of Au is 19.7 g
The chemical reaction may be
Au₂S₃ + 3H₂ → 2Au + 3H₂S
1 mole of Au₂S₃ gives 2 mole of Au
Then 0.0500 mol of Au₂S₃ gives
0.0500 × 2 / 1
= 0.10 moles.
To find mass
Mass = moles × molar mass
Moles = 0.10.
Molar mass = 197 g
Mass = 0.10 × 197
= 19.7 g
Hence the mass of Au produces is 19.7 g
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C) rocks and mineral particle. Topsoil is what you see in everyday life sooo you don’t even need a book for that but ok. I’TS 100% RIGHT though. Hope it helps
Answer:
The answer to your question is 9.075 g of CO₂
Explanation:
Data
mass of C₃H₈ = 39 g
mass of O₂ = 11 g
Balanced chemical reaction
C₃H₈ + 5O₂ ⇒ 3CO₂ + 4H₂
-Calculate the molar mass of the reactants
C₃H₈ = (12 x 3) + (8 x 1) = 36 + 8 = 44 g
O₂ = (16 x 2) = 32 g
-Calculate the limiting reactant
theoretical yield C₃H₈ / O₂ = 44/5(32) = 44/ 160 = 0.275
experimental yield C₃H₈/O₂ = 39/11 = 3.5
From the previous result, we conclude that the limiting reactant is O₂ because the experimental yield was higher than the theoretical yield.
-Calculate the mass of CO₂
160 g of O₂ ----------------- 3(44) g of CO₂
11 g of O₂ ------------------ x
x = (11 x 3(44)) / 160
x = 1452 / 160
x = 9.075 g of CO₂
In physics, the law of conservation of energy states that the total energy of an isolated system remains constant—it is said to be conserved over time. Energy can neither be created nor destroyed; rather, it transforms from one form to another. For instance, chemical energy can be converted to kinetic energy in the explosion of a stick of dynamite.
