Answer:
The answer to your question is 0.32 moles of water are needed.
Explanation:
Data
mass of CaC₂ = 10 g
mass of water = ?
Process
1.- Write the balanced reaction
CaC₂ + 2H₂O ⇒ C₂H₂ + Ca(OH)₂
Reactant Element Product
1 Ca 1
2 C 2
4 H 4
2 O 2
The reaction is balanced
2.- Convert mass of CaC₂ to moles
molecular mass CaC₂ = 40 + (2 x 12)
= 40 + 24
= 64 g
64 g of CaC₂ ----------------- 1 mol
10 g ----------------- x
x = (10 x 1) / 64
x = 10/64
x = 0.16 moles of CaC₂
3.- Calculate the moles of water
1 mol of CaC₂ ----------------- 2 moles of water
0.16 moles of CaC₂ --------- x
x = (0.16 x 2) / 1
x = 0.32 moles of water
Answer:
C
Explanation:
When the Kb is given, the Henderson-Hasselbalch equation can be used to calculate the pOH of a buffer solution:
pOH = pKb + log ([A⁻] / [HA]) = -log(Kb) + log ([BH+] / [B])
Here, moles can be used in place of the concentration since the pairs listed are both dissolved in 5L, which cancel due to the fraction in the logarithm.
a) pOH = -log(1.8 x 10⁻⁵) + log(1.5/1.0) = 4.92
pH = 14 - pOH = 14 - 4.92 = 9.08
b) pOH = -log(1.8 x 10⁻⁵) + log(1.0/1.5) = 4.57
pH = 14 - pOH = 14 - 4.57 = 9.43
c) pOH = -log(1.7 x 10⁻⁹) + log(1.5/1.0) = 8.95
pH = 14 - pOH = 14 - 8.95 = 5.05
d) pOH = -log(1.7 x 10⁻⁹) + log(1.0/1.5) = 8.59
pH = 14 - pOH = 14 - = 5.41
Answer:2kg
Explanation:
Mass =?
Acceleration = 3.0 m/s2
Force = 6.0N
Force = Mass x Acceleration
6 = Mass x 3
Mass =6/3 = 2Kg
its the fourth one
you have to add then round