Answer:
Number of moles = 0.042 mol
Explanation:
Given data:
Number of moles = ?
Mass of calcium carbonate = ?
Solution:
Formula:
Number of moles = mass/ molar mass
now we will calculate the molar mass of calcium carbonate.
atomic mass of Ca = 40 amu
atomic mass of C = 12 amu
atomic mass of O = 16 amu
CaCO₃ = 40 + 12+ 3×16
CaCO₃ = 40 + 12+48
CaCO₃ = 100 g/mol
Now we will calculate the number of moles.
Number of moles = 4.15 g / 100 g/mol
Number of moles = 0.042 mol
A stock solution is a solution of a known concentration. Stock solution has a high concentration and therefore, the known amount of stock solution is used for preparing different concentrations, by diluting the same with the known amount of the solvent being used, such as water.
Answer:
-81.5 degrees C or 191.5 K
Explanation:
We want to use Charles' gas law: V/T = V/T
Our initial volume is 3.20 L, and our initial temperature is 125 degrees C, or 125 + 273 = 398 degrees Kelvin.
Our new Volume is 1.54 L, but we don't know what the temperature is. So, we use the equation:
3.20 L / 398 K = 1.54 L / T ⇒ Solving for T, we get: T = 191.5 K
If we want this in degrees Celsius, we subtract 273: 191.5 - 273 = -81.5 degrees C
