Answer:
270 Joules
Explanation:
The specific heat capacity equation will be used for this question i.e.
Q = m. c. ΔT
Where; Q = Amount of heat
m = mass of substance
C = specific heat capacity of
substance
ΔT = change in temperature
(Final temp - initial temp)
However, for this unknown metal, we need to find the specific heat first by saying; C = Q / mΔT
Q= 135J, C=?, m= 10g, ΔT = (40-25 = 15°C)
C = 135 / 15 × 10
C = 135/150
C = 0.9 J/g°C
If the specific heat capacity of the unknown metal is 0.9 J/g°C, then at a mass of 20.0g, and a ΔT of 15°C, the amount of heat needed is:
Q = m. c. ΔT
Q = 20 × 0.9 × (40-25)
Q = 18 × 15
Q = 270J
270 Joules of heat is needed to increase the temperature of 20g of the metal from 25 - 40°C
Answer:
7 L of H₂.
Explanation:
The balanced equation for the reaction is given below:
2H₂ + O₂ —> 2H₂O
From the balanced equation above,
1 L of O₂ required 2 L of H₂.
Finally, we shall determine the volume of H₂ required to react with 3.5 L of O₂. This can be obtained as follow:
From the balanced equation above,
1 L of O₂ required 2 L of H₂.
Therefore, 3.5 L of O₂ will require
= 3.5 × 2 = 7 L of H₂.
Thus, 7 L of H₂ is required to for the reaction.
Examining the given reaction:
Li2O + H2O ........> 2LiOH
we find that, 1 mole of Li2O is required to react with one mole of H2O in order to produce two moles of LiOH.
Therefore, the ration between the required Li2O and H2O is 1:1
Based on this, 2.2 moles of H2O (water) are required to react with 2.2 moles of Li2O
Answer: c12 has a mass of 12 amu
Explanation:
mass of one mole of c12 = g. So mass of 1 atom of c12 = 1.9927e-23g
