Zinc is amphoteric which means it reacts with both acids and alkalis.
The balanced equation is: Zn + 2NaOH + 2H2O --> Na2Zn(OH)4 + H2(g).
Sodium zincate and hydrogen gas are the products.
Answer:
D
Explanation:
A reaction becomes spontaneous when the value of the change in free energy is negative.
The relationship between the enthalpy, the entropy and the free energy in a chemical reaction is given below:
G = H – TS
Now, let’s input the values that we have.
One important thing to note is that we have to convert the KJ to Joules and this mean we have to multiply by a conversion factor of 1000. This mean 33KJ is 33,000J
33,000 = 92,200 - 198.7T
33,000 - 92,200 = -198.7T
-59,200 = - 198.7T
T = 59,200/198.7
T = 298k
Answer:
5 g of heptane were burned.
Explanation:
Given data:
Mass of CO₂ produced = 15.5 g
Mass of heptane burned = ?
Solution:
Balance chemical equation:
C₇H₁₆ + 11O₂ →7CO₂ + 8H₂O
First of all we will calculate the moles of CO₂ produced.
Number of moles = mass / molar mass
Molar of CO₂ = 44 g/mol
Number of moles = 15.5 g / 44 g/mol
Number of moles = 0.3523 mol
Now we will compare the moles of CO₂ and C₇H₁₆ from balance chemical equation
CO₂ : C₇H₁₆
7 : 1
0.3523 : 1/7 × 0.3523 = 0.05 mol
Mass of C₇H₁₆:
Number of moles = mass / molar mass
Mass = number of moles × molar mass
Mass = 0.05 mol / 100 g/mol
Mass = 5 g
Answer:
The hardness is more than 2.5. Hope this helps.