Answer:
2.04 x 10²⁴ molecules
Explanation:
Given parameters:
Mass of Be(OH)₂ = 145.5g
To calculate the number of molecules in this mass of Be(OH)₂ we follow the following steps:
>> Calculate the number of moles first using the formula below:
Number of moles = mass/molarmass
Since we have been given the mass, let us derive the molar mass of Be(OH)₂
Atomic mass of Be = 9g
O = 16g
H = 1g
Molar Mass = 9 + 2(16 + 1)
= 9 + 34
= 43g/mol
Number of moles = 145.5/43 = 3.38mol
>>> We know that a mole is the amount of substance that contains Avogadro’s number of particles. The particles can be atoms, molecules, particles etc. Therefore we use the expression below to determine the number of molecules in 3.38mol of Be(OH)₂:
Number of
molecules= number of moles x 6.02 x 10²³
Number of molecules= 3.38 x 6.02 x 10²³
= 20.37 x 10²³ molecules
= 2.04 x 10²⁴ molecules
Answer:
The new temperature will be 565.83 K.
Explanation:
Gay Lussac's law establishes the relationship between the temperature and the pressure of a gas when the volume is constant. This law says that the pressure of the gas is directly proportional to its temperature. This means that if the temperature increases, the pressure will increase; or if the temperature decreases, the pressure will decrease.
In other words, Gay-Lussac's law states that when a gas undergoes a constant volume transformation, the ratio of the pressure exerted by the gas temperature remains constant:
When an ideal gas goes from a state 1 to a state 2, it is true:
In this case:
- P1= 180 kPa
- T1= 291 K
- P2= 350 kPa
- T2= ?
Replacing:
Solving:
T2= 565.83 K
<u><em>The new temperature will be 565.83 K.</em></u>
Because of the surface tention.
Heat energy is calculated by multiplying the mass, specific heat capacity of a substance by the change in temperatures. Therefore,the heat lost by water will be given by mass of water (in kg) × specific heat capacity of water × change in temperature. This heat will be equivalent to the heat gained by the spoon calculated by mass of the spoon by specific heat capacity by change in temperature. (considering that the specific heat capacity of gold is 125.6 J/kg/k)
hence, 0.05 kg × 49 × 125.6 J/kg/k = 307.72 Joules
therefore, heat lost by water is equivalent to 307.72 Joules
