Latent heat of melting is the energy that a solid absorbs to change its phase as its liquid. During this process, since all energy is used to change the phase, the temperature is constant.
Here the latent energy of melting for 1 g of ice is 80 calories and that 1 g of ice only absorbed 60 calories. hence the phase is not changed because it requires more 20 calories to melt.
Hence 1 g of ice remains as its solid phase (ice).
*Answer:
Option A: 59.6
Explanation:
Step 1: Data given
Mass of aluminium = 4.00 kg
The applied emf = 5.00 V
watts = volts * amperes
Step 2: Calculate amperes
equivalent mass of aluminum = 27 / 3 = 9
mass of deposit = (equivalent mass x amperes x seconds) / 96500
4000 grams = (9* amperes * seconds) / 96500
amperes * seconds = 42888888.9
1 hour = 3600 seconds
amperes * hours = 42888888.9 / 3600 = 11913.6
amperes = 11913.6 / hours
Step 3: Calculate kilowatts
watts = 5 * 11913.6 / hours
watts = 59568 (per hour)
kilowatts = 59.6 (per hour)
The number of kilowatt-hours of electricity required to produce 4.00kg of aluminum from electrolysis of compounds from bauxite is 59.6 kWh when the applied emf is 5.00V
Answer:
a) 1.866 × 10 ⁻¹⁹ J b) 3.685 × 10⁻¹⁹ J
Explanation:
the constants involved are
h ( Planck constant) = 6.626 × 10⁻³⁴ m² kg/s
Me of electron = 9.109 × 10 ⁻³¹ kg
speed of light = 3.0 × 10 ⁸ m/s
a) the Ek ( kinetic energy of the dislodged electron) = 0.5 mu²
Ek = 0.5 × 9.109 × 10⁻³¹ × ( 6.40 × 10⁵ )² = 1.866 × 10 ⁻¹⁹ J
b) Φ ( minimum energy needed to dislodge the electron ) can be calculated by this formula
hv = Φ + Ek
where Ek = 1.866 × 10 ⁻¹⁹ J
v ( threshold frequency ) = c / λ where c is the speed of light and λ is the wavelength of light = 358.1 nm = 3.581 × 10⁻⁷ m
v = ( 3.0 × 10 ⁸ m/s ) / (3.581 × 10⁻⁷ m ) = 8.378 × 10¹⁴ s⁻¹
hv = 6.626 × 10⁻³⁴ m² kg/s × 8.378 × 10¹⁴ s⁻¹ = 5.551 × 10⁻¹⁹ J
5.551 × 10⁻¹⁹ J = 1.866 × 10 ⁻¹⁹ J + Φ
Φ = 5.551 × 10⁻¹⁹ J - 1.866 × 10 ⁻¹⁹ J = 3.685 × 10⁻¹⁹ J
From ideal gas equation that is PV=nRT
n(number of moles)=PV/RT
P=760 torr
V=4.50L
R(gas constant =62.363667torr/l/mol
T=273 +273=298k
n is therefore (760torr x4.50L) /62.36367 torr/L/mol x298k =0.184moles
the molar mass of NO2 is 46 therefore density= 0.184 x 46=8.464g/l
The scientific form is
So, the form of scientific notation is
