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.
Answer:
Percentage mass of copper in the sample = 32%
Explanation:
Equation of the reaction producing Cu(NO₃) is given below:
Cu(s)+ 4HNO₃(aq) ---> Cu(NO₃)(aq) + 2NO₂(g) + 2H₂O(l)
From the equation of reaction, 1 mole of Cu(NO₃) is produced from 1 mole of copper. Therefore, 0.010 moles of Cu(NO₃) will be produced from 0.010 mole of copper.
Molar mass of copper = 64 g/mol
mass of copper = number of moles * molar mass
mass of copper = 0.01 mol * 64 g/mol = 0.64 g
Percentage by mass of copper in the 2.00 g sample = (0.64/2.00) * 100%
Percentage mass of copper in the sample = 32%
D. dishwashing Soap/Liquid
Answer:
Option D: More than 30 seconds
Explanation:
The enzyme CATALASE is found in almost all living organisms. CATALASE helps in the decomposition of one substance into another substance. CATALASE will breaks down hydrogen peroxide into water and oxygen.
When the potatoes were boiled it will surely produce no bubbles because the heat would have degrade the enzyme - catalase While the potatoes at room temperature potato produced the most bubbles because catalase works best at a room temperature.
If the potato solution was boiled for 10 minutes and cooled for 10 minutes before being tested, the average time for the disks to float to the surface of the hydrogen peroxide solution would be MORE THAN 30 SECONDS
Answer:
32.25
Explanation:
8NH3 + 3Cl2 → 6NH4Cl + N2
NH3 = 17 g/mol
number of moles = 1
NH4Cl= 43 g/mol
number of moles = 3/4
mass= 43 × ¾ ≈ 32.25 g
