Answer:
-26.125 kj
Explanation:
Given data:
Mass of water = 250.0 g
Initial temperature = 30.0°C
Final temperature = 5.0°C
Amount of energy lost = ?
Solution:
Formula:
Q = m.c. ΔT
Q = amount of heat absorbed or released
m = mass of given substance
c = specific heat capacity of substance
ΔT = change in temperature
ΔT = T2 - T1
ΔT = 5.0°C - 30.0°C
ΔT = -25°C
Specific heat of water is 4.18 j/g.°C
Now we will put the values in formula.
Q = m.c. ΔT
Q = 250.0 g × 4.18 j/g.°C × -25°C
Q = -26125 j
J to kJ
-26125 j ×1 kj /1000 j
-26.125 kj
A lit candle needs to draw oxygen from the air in order to continue burning. ... Thus, oxygen inside the glass jar will decrease and it gets filled with carbon dioxide, and eventually the candle's flame will Extinguish.
Answer:
3,855.532 grams
Explanation:
1 pound = 453.592 grams
8.50 = ? grams
--> 8.50 * 453.592 = 3,855.532 grams.
Answer:
241 nm, it is UV light range
Explanation:
The minimum energy needed required to break the oxygen-oxygen bond = 495 kJ/mol
Energy needed for 1 molecule of oxygen = 495 × 10³ J / avogadro's constant = 495 × 10³ J / ( 6.02 × 10²³) = 8.223 × 10⁻¹⁹ J
Energy = hv
where h = Planck constant = 6.626 × 10 ⁻³⁴ m²kg/s and v = frequency
c speed of light = vλ
c / λ = v
E = hc / λ
λ = hc / E = (6.626 × 10 ⁻³⁴ m²kg/s × 3.0 × 10 ⁸ m/s) / (8.223 × 10⁻¹⁹ J) = 2.41 × 10⁻⁷m = 241 nm
UV light wavelength is between 400 nm - 10 nm
As,
Kw = [H+] [OH-]
For water, [H+] = [OH-]
Therefore we can write
Kw = [H+]²
9.311 × 10-14 = [H+]²
[H+] =
3.04 × 10-7 = [OH-]
Ph = - log [H+]
= - log (
3.04 × 10-7)
= 6.52
Thus, Ph = PoH = 6.52
