Question

part a
0.45 mol of na2so4 in 7.36 l of solution
express the molarity in moles per liter to two significant figures.
molarity =
m
submit request answer
part b
36.6 g c2h6o in 2.04 l of solution
express the molarity in moles per liter to three significant figures.
molarity =
m
submit request answer

Explanation:

Part A

Step1: Recall molarity formula

Molarity ($M$) is defined as $M=\frac{n}{V}$, where $n$ is the number of moles and $V$ is the volume of the solution in liters.

Step2: Substitute values

Given $n = 0.45$ mol and $V=7.36$ L. So $M=\frac{0.45}{7.36}$.

Step3: Calculate and round

$M=\frac{0.45}{7.36}\approx0.06114$. Rounding to two - significant figures, $M = 0.061$ M.

Part B

Step1: Calculate molar mass of $C_2H_6O$

The molar mass of $C_2H_6O$: $M_{C_2H_6O}=2\times12.01 + 6\times1.01+16.00=46.08$ g/mol.

Step2: Calculate number of moles

Using $n=\frac{m}{M}$, where $m = 36.6$ g and $M = 46.08$ g/mol. So $n=\frac{36.6}{46.08}\approx0.7943$ mol.

Step3: Calculate molarity

Using $M=\frac{n}{V}$, with $n = 0.7943$ mol and $V = 2.04$ L. So $M=\frac{0.7943}{2.04}\approx0.389$ M.

Answer:

Part A: 0.061 M
Part B: 0.389 M