Give me one second. Let me see
By law of conservation of energy, the amount of heat lost
by the metal should be equal to the amount of heat gained by water. That is,
the change in energy (expressed in enthalpies) should be equal:
- (ΔH)metal = (ΔH)water
Take note of the negative sign in front of (ΔH)metal, this
means that heat is lost by this metal.
Where ΔH or change in enthalpy is:
ΔH = m Cp (T2 – T1)
So,
- 15 g (Cp) (23 °C – 99 °C) = 75 g (4.18 J/g * °C) (26 °C –
23 °C)
1,140 Cp = 940.5
<span>Cp = 0.825 J/g * °C (ANSWER)</span>
The answer is 0.492 because there are 100 meters in a hectometer, and 49.2/100 is 0.492
7.5 ppm
<h3>Further explanation</h3>
Given
1000 g of water
0.0075g of Ca²⁺ ion
Required
the concentration in ppm by mass of Ca²⁺
Solution
ppm = part per million
solvent = water ⇒ ppm = 1 mg/L(water density is 1 kg / L) or mg/kg
Convert g to mg of Ca²⁺ ion :
0.0075 g = 7.5 x 10⁻³ g = 7.5 mg
Convert g to kg of water :
1000 g = 1 kg water
So the concentration of Ca²⁺ ion :
= 7.5 mg / 1 kg
= 7.5 ppm
I think it's B) 30 m/s going down.
