Answer:
B. The water must gain thermal energy from its surroundings.
Explanation:
Boiling is the process whereby a substance is changed from a liquid state to a gaseous state due to the application of heat. For boiling to be achieved, a liquid substance must reach or exceed its boiling point, which is the specific temperature at which a specific liquid boils.
For this change of state i.e. from liquid to gas, to occur, atoms or molecules of the liquid must gain kinetic energy and move faster. However, this kinetic energy cannot be attained without a rise in temperature, which causes the molecules to gain THERMAL ENERGY or heat energy and move fast. Thermal energy is the energy that arises from a hot substance.
Therefore, for water to boil at a given pressure, it must gain thermal energy from its external surroundings, which causes its molecules to have an increased kinetic energy and move faster. This fast movement of the molecules causes the transition of phases (from liquid to gas).
when the metal is lost heat and the calorimeter of water is gained the heat
and when the heat lost = the heat gained so,
(M*C*ΔT)m = (M*C*ΔT)w
when Mm= mass of the metal = 30 g
Δ Tm = (80-25) = 55 °C
and Mw = mass of water = 100 g
Cw is the specific heat of water = 4.181 J/g.°C
ΔTw = (25-20) = 5 °C
so by substitution:
∴ 30* Cm*55 = 100 * 4.181 * 5
∴Cm (specific heat of metal) = (100*4.181*5)/(30*55)
∴C of metal = 1.267 J/g.°C
Answer:
A) H2O > HCCH > NH3 > CH3CH3
Explanation:
H2O is known as a neural compound which a pH close to 7.0. This however makes it more acidic due to it having the lowest pH when compared to the others in the option.
The other options however have their acidic strength as follows: HCCH > NH3 > CH3CH3. This explains why the pattern of decreasing acidic strength is H2O > HCCH > NH3 > CH3CH3
To solve the question you use the following formula:
concentration (1) × volume (1) = concentration (1) × volume (1)
3 M × volume (1) = 1.8 M × 50 mL
volume (1) = (1.8 M × 50 mL) / 3 M = 30 mL
