Answer:
Earth is often called the ocean planet because it is 70% covered in water.
Explanation:
D.
Answer:
68000J/kg
Explanation:
Given parameters:
Mass of the substance = 0.5kg
Quantity of heat transferred to the body = 34000J
Unknown:
Specific latent heat of fusion = ?
Solution:
The specific latent heat is usually involve in phase changes;
H = mL
H is the quantity of heat supplied
m is the mass
L is the specific latent heat
Insert the parameters and solve;
34000 = 0.5 x L
L = 
= 68000J/kg
Answer: C. A Chemical Change
Explanation:
A chemical change is one that occurs when new substances are produced preceding a chemical reaction ( the mixing or combination of one substance with another).
From the experiment by Jasmine, since light was produced from the mixture, energy is being released which is due to a chemical change.
Answer:
81 molecules
Explanation:
The reaction between C5H12 and O2 is a combustion reaction and is represented by the following equation;
C5H12 + 8O2 --> 5CO2 + 6H2O
The ratio of C5H12 to O2 from the above equation is 1 : 8.
Aplying the conditins of the question; 24 molecules each of C5H12 and O2 we have;
3C5H12 + 24O2 --> 15CO2 + 18H2O
This means we have 24 - 3 = 21 molecules of C5H12 that are unreacted.
Total molecules is given as;
3(C5H12) + 24(O2) + 15(CO2) + 18(H2O) + 21(Unreacted C5H12) = 81 molecules
Answer:
Explanation:
13 ) symbol of enthalpy change = Δ H .
14 ) enthalpy change is nothing but heat absorbed or evolved .
During fusion enthalpy change
Δ H .= m Lf , m is mass and Ls is latent heat of fusion
During evaporation, enthalpy change
Δ H .= m Lv , m is mass and Lv is latent heat of evaporation
during temperature rise , enthalpy change
Δ H = m c Δ T
In case of gas , enthalpy change can be calculated by the following relation
Δ H = Δ E + W , Δ E is change in internal energy , W is work done by gas.
15 ) When enthalpy change is negative , that means heat is released to the environment .So reaction is called exothermic .
when heat is absorbed enthalpy change is positive . Reaction is endothermic.
