Answer:
The answer to your question is: = 2.52 x 10²¹ molecules
Explanation:
mass of fuel = 13.56 - 13.53 = 0.04 g of fuel
mass of oxygen = ?
mass of water = 0.054 g
mass of carbon dioxide = 0.1198 g
To solve this problem just remember the Lavoisier law of conservation of mass that says: Mass is neither created nor destroyed in chemical reactions,
Reaction:
Fuel + Oxygen ⇒ Water + Carbon dioxide
0.04 + mass O2 ⇒ 0.054 + 0.1198
mass O2 = 0.054 + 0.1198 - 0.04
mass O2 = 0.1338 g
MW O2 = 32
1 mol of O2 -------------------- 32 g
x ------------------- 0.1338g
x = 0.1338(1) / 32 = 0.0042 moles
1 mol ----------------- 6,023 x 10 ²³ molecules
0.0042 moles ----- x
x = 0.0042 (6,023 x 10 ²³ ) / 1 = 2.52 x 10²¹ molecules
Answer:
A spinning ball creates a "Centrifugal Force" because you give it the "energy" to spin. A ball that is not moving does not require any external energy to keep it still.
Explanation
A. Phase changing. When phase changes nothing chemically changes about the substance, its still the same thing.
Answer : The enthalpy change is, 7.205 KJ
Solution :
The conversions involved in this process are :
Now we have to calculate the enthalpy change.
where,
= enthalpy change = ?
m = mass of water = 10 g
= specific heat of solid water = 2.09 J/gk
= specific heat of liquid water = 4.18 J/gk
n = number of moles of water =
= enthalpy change for fusion = 6.01 KJ/mole = 6010 J/mole
Now put all the given values in the above expression, we get
(1 KJ = 1000 J)
Therefore, the enthalpy change is, 7.205 KJ