Answer:
373.88 torr
Explanation:
P1 = 350 torr
T1 = 20°C = (20 + 273.15)K = 293.15K
P2 = ?
T2 = 40°C = (40 + 273.15)K = 313.15K
From pressure law,
Pressure of a given mass of gas is directly proportional to its temperature.
P = KT
K = P / T
P1 / T1 = P2 / T2
Solve for P2
P2 = (P1 * T2) / T1
P2 = (350 * 313.15) / 293.15
P2 = 109602.5 / 293.15
P2 = 373.878 torr
P2 = 373.88 torr
The new pressure of the gas would be 373.88 torr.
Answer:
b. 54.9%
Explanation:
An emerald gemstone has the formula Be₃Al₂Si₁₆O₁₈. We can find the mass of each element in 1 mole of Be₃Al₂Si₁₆O₁₈ by multiplying the molar mass of the element by its atomicity.
Be: 3 × 9.01 g = 27.03 g
Al: 2 × 26.98 g = 53.96 g
Si: 16 × 28.09 g = 449.4 g
O: 18 × 16.00 g = 288.0 g
Total mass = 818.4 g
The mass percentage of silicon is:
(449.4 g / 818.4 g) × 100% = 54.91%
Answer:
41.63g
Explanation:
Given parameters:
Volume of CaCl₂ = 500mL = 0.5L
Concentration = 0.75mol/L
Unknown:
Mass of the solute needed = ?
Solution:
The mass of the solute can be derived using the expression below;
Mass = number of moles x molar mass
But,
Number of moles = Concentration x Volume
So;
Mass = Concentration x Volume x molar mas
Molar mass of CaCl₂ = 40 + 2(35.5) = 111g/mol
Mass = 0.75 x 0.5 x 111 = 41.63g
The population decreases when the birth rate is less than the death rate.
the second option is the correct answer i PROMISE