Answer:
The potential wrt. calomel is 1.254 V
Explanation:
Given:
Potential wrt. silver chloride 
V
Potential wrt. saturated silver chloride 
V
Potential wrt. SCE 
V
Now potential wrt. hydrogen is given by,
V
And we find for potential wrt. calomel,
potential wrt. hydrogen + potential wrt. SEC
V
Therefore, the potential wrt. calomel is 1.254 V
Answer:
- <u>C₂H₄</u> (option number 4)
Explanation:
A hydrocarbon with a <em>double bond</em> in its carbon skeleton is an alkene and has the general form:
-
.
This is, the number of hydrogen atoms is twice the number of carbon atoms.
On the other hand, alkanes have only single bonds, and the compounds with a triple bond in its carbon skeleton are alkynes.
Review each choice:
1) <u>C₃H₈:</u>
- In this case, the number of hydrogen atoms is 2×3 + 2 = 6 + 2 = 8, which is corresponds to an alkane, not an alkene.
2)<u> C₂H₆</u>
- For this, the number of hydrogen atoms is 2 × 2 + 2 = 4 + 2 = 6. Again an alkane, not alkene.
3) <u>CH₄</u>
- Hydrogen atoms: 1 × 2 + 2 = 4 ⇒ an alkane
4) <u>C₂H₄ </u>
- Hydrogen atoms: 2 × 2 = 4. This is precisely the relation for an alkene, so this is the hydrocarbon that has a double bond in its carbon skeleton.
- The chemical formula may be writen as CH₂ = CH₂, to show the double bond.
So, this is the correct answer.
5) <u>C₂H₂</u>
- Hydrogen atoms: 2 × 2 - 2 = 4 - 2 = 2. This relation of carbon and hydrogen atoms corresponds to a compound with triple bond, i.e an alkyne: CH≡CH.
One mole of a substance contains 6.02×10∧23 particles,
1 mole of a aluminium contains 27 g
35 g of aluminium contains 35/27 =1.296 moles
Thus, the number of particles will be 1.296 × 6.02 ×10∧23
= 7.804 × 10∧23 particles,
Hence, 35 g of Aluminium contains 7.804 × 10∧23 atoms
Answer:
The statement that is not true is: 'Temperature does not affect the reaction rate'.
Explanation:
a) Temperature can change a reaction rate. <u> This is true</u>
Increasing the temperature increases the reaction rates because of the disproportionately large increase in the number of high energy collisions. It is only these collisions (possessing at least the activation energy for the reaction) which result in a reaction.
For example, the time taken to melt a metal will be much higher at a lower temperature but it will decrease as soon as we increase the temperature
b) The amount of reactants can increase the reaction rate.<u> This is true</u>
A higher concentration of reactants leads to more effective collisions per unit time, which leads to an increased reaction rate.
c) Temperature can decrease the reaction rate. <u>This is true </u>
Decreasing the temperature decreases the reaction rates because of the decrease in the number of high energy collisions. It will result in a slower reaction.
d) Temperature does not affect the reaction rate. <u>This is not true. </u>
The reaction rate is temperature dependent. The reaction rate increases with higher temperature and decreases with lower temperature.
