Answer:
2.5 g
Explanation:
Given data:
Masses of sample = 0.12 g, 1.8 g, 0.562 g
Combine mass of samples = ?
Solution:
When we add or subtract the values the number of significant figures after decimal in result must be equal to the given measurement having less number of decimal places.
0.12 g + 1.8 g + 0.562 g
2.482 g
In given three measurements 1.8 has less number of significant figure after decimal point which is only one digit. Thus the final value must contain one digit after decimal.
we will round of 2.482 g.
2.5 g
because the next digit after 4 is 8 that's why we will round 4 to 5.
Answer:
0.4076 g
Explanation:
Kp is the equilibrium constant based on pressure and depends only on gas substances. For a generic reaction
aA + bB ⇄ cC + dD
, where pX is the pressure of X in equilibrium.
For the reaction Kp = pCO₂
pCO₂ = 0.026 atm
The system is in equilibrium at the beginning. The compression occurs at a constant temperature, so using Boyle's law
P1V1 = P2V2
0.026*10 = P2*0.1
P2 = 2.6 atm
The reaction will reach again the equilibrium, and pCO₂ = 0.026 atm, then the rest will form MgCO₃, which will be 2.6 - 0.026 = 2.574 atm.
By the ideal gas law:
PV = nRT, where P is the pressure, V is the volume, n is the number of moles, R is the gas constant (0.082 atm*L/mol*K), and T is the temperature.
2.574*0.1 = n*0.082*650
53.3n = 0.2574
n = 4.83x10⁻³ mol
The stoichiometry of the reaction is 1 mol of MgCO₃ for 1 mol of CO₂, so it will form 4.83x10⁻³ mol of MgCO₃ .
The molar mass is:
MgCO₃: 24 g/mol of Mg + 12 g/mol of C + 3*16 g/mol of O = 84 g/mol
The mass formed is the molar mass multiplied by the number of moles:
m = 84x4.83x10⁻³
m = 0.4076 g
Answer: C: limestone cave formations