Answer:
Explanation:
we know that
ΔH=m C ΔT
where ΔH is the change in enthalpy (j)
m is the mass of the given substance which is water in this case
ΔT IS the change in temperature and c is the specific heat constant
we know that given mass=2.9 g
ΔT=T2-T1 =98.9 °C-23.9°C=75°C
specific heat constant for water is 4.18 j/g°C
therefore ΔH=2.9 g*4.18 j/g°C*75°C
ΔH=909.15 j
Answer:125.0964g
Explanation:
Density = mass/volume
Density = 2.7 gcm-3
Volume=2.7*1.2*14.3=46.332
Mass=?
Mass= density* volume
= 2.7× 46.332=125.0964g
the average speed is 23.4 km per hour cause it is total distance over total time equal to average speed
Yes, when molten candle wax solidifies it is a chemical reaction
<u>Explanation:</u>
Basically Wax is crystalline so once the candle light melts it freezes taking back the solid state to the room temperature.
When the room temperature is below the freezing point, the liquid candle wax, turns into solid state again, therefore this process is called solidification. The process of freezing or solidification is a process when an object turns liquid and freezes back to solid state.
Indeed, Yes, when molten candle wax solidifies it is a chemical reaction
The mass of sodium sulphate, Na₂SO₄, required to prepare the solution is 10.65 g
<h3>How to determine the mole of sodium sulphate Na₂SO₄</h3>
- Volume = 250 mL = 250 / 1000 = 0.25 L
- Molarity = 0.3 M
Mole = Molarity x Volume
Mole of Na₂SO₄ = 0.3 × 0.25
Mole of Na₂SO₄ = 0.075 mole
<h3>How to determine the mass of sodium sulphate Na₂SO₄</h3>
- Molar mass of Na₂SO₄ = 142.05 g/mol
- Mole of Na₂SO₄ = 0.075 mole
Mass = mole × molar mass
Mass of Na₂SO₄ = 0.075 × 142.05
Mass of Na₂SO₄ = 10.65 g
Thus, 10.65 g of Na₂SO₄ is needed to prepare the solution.
Learn more about molarity:
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