Answer:
Thermal energy is transferred from hot places to cold places by convection. Convection occurs when warmer areas of a liquid or gas rise to cooler areas in the liquid or gas.
Explanation:
<span><span>Atomic number36,</span><span>Atomic mass<span>83.80 g.mol -1,</span></span><span>Density<span>3.73 10-3 g.cm-3 at 20°C,</span></span><span>Melting point- 157 °C,</span><span>Boiling point<span>- 153° C</span></span></span>
Answer:
The final and initial concentration of the acid and it's conjugate base are approximately equal, that is we use the weak acid approximation.
Explanation:
The Henderson-Hasselbalch is used to calculate the pH of a buffer solution. It depends on the weak acid approximation.
Since the weak acid ionizes only to a small extent, then we can say that [HA] ≈ [HA]i
Where [HA] = final concentration of the acid and [HA]i = initial concentration of the acid.
It also follows that [A^-] ≈ [A^-]i where [A^-] and[A^-]i refer to final and initial concentrations of the conjugate base hence the answer above.
Answer:
Option D. 230 J
Explanation:
We'll begin by calculating the temperature change of the iron. This can be obtained as follow:
Initial temperature (T₁) = 50 °C
Final temperature (T₂) = 75 °C
Change in temperature (ΔT) =?
ΔT = T₂ – T₁
ΔT = 75 – 50
ΔT = 25 °C
Thus, the temperature change of the iron is 25 °C.
Finally, we shall determine the amount of heat energy used. This can be obtained as follow:
Mass (M) = 20 g
Change in temperature (ΔT) = 25 °C
Specific heat capacity (C) = 0.46 J/gºC
Heat (Q) =?
Q = MCΔT
Q = 20 × 0.46 × 25
Q = 230 J
Thus, the amount of heat used was 230 J
Answer:
4
Explanation:
Avogadro’s number represent the number of the constituent particles which are present in one mole of the substance. It is named after scientist Amedeo Avogadro and is denoted by 
.
Also, it is the number of particles in exactly 12.000 g of isotope carbon 12.
Avogadro constant:-
Hence,
Mass of 
= 131.293+ n18.998 g
So,
molecules have a mass of 131.293+ n18.998 g
Also,
molecules have a mass of 
g
So,
molecules have a mass of 
g
Also, given mass = 0.172 g
Thus,
<u>Thus, value of n is 4.</u>
