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QUESTION;
Understanding the enthalpy definition=
Measurements show that the enthalpy of a mixture of gaseous reactants increases by 125.kJ during a certain chemical reaction, which is carried out at a constant pressure. Furthermore, by carefully monitoring the volume change it is determined that -71.kJ of work is done on the mixture during the reaction. Calculate the change in enthalpy of the gas mixture during the reaction and determine if the reaction is endothermic or exothermic.
ANSWER: The change in enthalpy of the gas mixture during the reaction is 54.kJ
The reaction is endothermic.
EXPLANATION: Enthalpy is the heat change in a system.
To calculate enthalpy we use the formula below;
H = E + PV
H is the enthalpy
E is the energy used in the reaction
PV is the product of pressure and volume which is refered to as the work done in the system
Using the equation above
H = 125 + (-71) = 54.kJ
An endothermic reaction is a type of reaction where heat is gained by the system from it's environment, and the enthalpy of such system is positive. While an Exothermic reaction is a type of reaction where heat is lost by the system to it's environment, and the enthalpy of such system is negative.
Because our enthalpy value is positive, this is an endothermic reaction.
If the net force is doubled, the acceleration would also be doubled.
This is the answer
Answer: oprion <span>A. Catalysts can only increase the rate of reaction for compounds that do react.
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Explanation:
Such as the right choice states a catalyst cannot make react two materials that cannot chemically react.
The catalysts modify the rate (speed) of a reaction between chemicals.
The definition of catalyst is a substance that increases the speed of a chemical reaction by modifying the activation energy but that is not consumed in the reaction.
Then three facts must be highlithed about catalyst:
1) Catalysts are not included in the chemical equation since they do not increase the amount of product that can be obtained (they do not change the theoretical yield of the reaction).
2) Catalysts change the path that the reactants take to yield the products, which is how the energy activation is changed.
3) As consequence, catalysts are not consumed during the reaction.
True. Each contour line on a topographic map represent a certain elevation; the closer they are, the steeper the surface is. All points on a contour line are the same elevation.
Answer:
18.58 moles of Cu
Solution:
Data Given:
Chemical Formula of Tennantite = Cu₁₂As₄S₁₃
Mass of Cu₁₂As₄S₁₃ = 2290 g
M.Mass of Cu₁₂As₄S₁₃ = 1479.06 g.mol⁻¹
Step 1: Calculate Moles of Cu₁₂As₄S₁₃ as,
Moles = Mass ÷ M.Mass
Putting values,
Moles = 2290 g ÷ 1479.06 g.mol⁻¹
Moles = 1.548 mol
Step 2: Calculate Moles of Cu,
As,
1 mole of Cu₁₂As₄S₁₃ contains = 12 moles of Cu
So,
1.548 mol of Cu₁₂As₄S₁₃ will contain = X moles of Cu
Solving for X,
X = (1.548 mol × 12 mol) ÷ 1 mol
X = 18.58 moles of Cu