Answer: 
Explanation:-
Single replacement reaction is a chemical reaction in which more reactive element displaces the less reactive element from its salt solution.
As zinc is more reactive than copper, it could easily displace copper from its aqueous solution and thus leads to formation of zinc (II) sulfate and pure copper.
The chemical reaction can be represented as :

The phases are represented as (s) for solid sate, (l) for liquid state, (g) for gaseous state and (aq) for aqueous state.
Answer:
6,500 gm of steam require= 3,510 kilo calories (approx)
Explanation:
Every 1 gram of water at 100° C absorb 540 calories
So,
Total water = 6.5 kg = 6,500 gram
So,
6,500 gm of steam require = 6,500 x 540
6,500 gm of steam require= 3,510 kilo calories (approx)
Answer:
According to Le Chatelier's principle, increasing the reaction temperature of an exothermic reaction causes a shift to the left and decreasing the reaction temperature causes a shift to the right.
Explanation:
C6H12O6(s) + 6O2(g) ⇌6CO2(g) + 6H2O(g)
We are told that the forward reaction is exothermic, meaning heat is removed from the reacting substance to the surroundings.
According to Le Chatelier's principle,
1. for an exothermic reaction, on increasing the temperature, there is a shift in equilibrium to the left and formation of the product is favoured.
2. if the temperature of the system is decreased, the equilibrium shifts to right and the formation of the reactants is favoured.
3. if the reaction temperature is kept constant, the system is at equilibrium and there is no shift to the right nor to the left.
Answer:
Given: 42 g of N2
Solve for O2 mass that contains the same number of molecules to 42 g of N2.
Solve for the number of moles in 42 g of N2
1 mole of N2 = (14 * 2) g = 28 g so the number of moles in 42 g of N2 is equal to 42 g / 28 g per mole = 1.5 moles
Solve for mass of 1 mole of oxygen
1 mole of O2 = 16 g * 2 = 32 g per mole
Solve for the mass of 1.5 moles of oxygen
mass of 1.5 moles of O2 = 32 g per mole * 1.5 moles
mass of 1.5 moles of O2 = 48 g
So 48 g of O2 contains the same number of molecules as 42 g of N2