Answer:
Option 3. The catalyst does not affect the enthalpy change (
) of a reaction.
Explanation:
As its name suggests, the enthalpy change of a reaction () is the difference between the enthalpy of the products and the reactants.
On the other hand, a catalyst speeds up a reaction because it provides an alternative reaction pathway from the reactants to the products.
In effect, a catalyst reduces the activation energy of the reaction in both directions. The reactants and products of the reaction won't change. As a result, the difference in their enthalpies won't change, either. That's the same as saying that the enthalpy change of the reaction would stay the same.
Refer to an energy profile diagram. Enthalpy change of the reaction measures the difference between the two horizontal sections. Indeed, the catalyst lowered the height of the peak. However, that did not change the height of each horizontal section or the difference between them. Hence, the enthalpy change of the reaction stayed the same.
8 valence electrons are found in noble gases. Since noble gases have 8 valence electrons that means they have a full shell - which makes them unreactive
Answer:
69.8 kilo Pasacl is the pressure of the hydrogen gas.
Explanation:
Pressure at which hydrogen gas collected = p = 101.2 kilo Pascals
Vapor pressure water = 
= 31.4 kilo Pascals
The pressure of hydrogen gas = P
The pressure at which gas was collected was sum of vapor pressure of water and hydrogen gas.
69.8 kilo Pasacl is the pressure of the hydrogen gas.
Answer:
Absolute zero temperature: Absolute zero is the temperature at which a substance have very low internal energy or in other words no heat energy in the particle.
Explanation: The temperature is very low and the particles are very cold. On cooling, speed of particle decrease. On the Celsius scale, - 273.15 is the absolute zero and on the Kelvin scale, 0 k is the absolute zero. On absolute zero temperature, the movement in the particles occurs at very low speed near to zero.
