First calculate for the molar mass of the given formula unit, CaCO₃. This can be done by adding up the product when the number of atom is multiplied to its individual molar mass as shown below.

molar mass of CaCO₃ = (1 mol Ca)(40 g Ca/mol Ca) + (1 mol C)(12 g of C/1 mol of C) + (3 mols of O)(16 g O/1 mol O) = 100 g/mol of CaCO₃

Then, divide the given amount of substance by the calculated molar mass.
number of moles = (20 g)(1 mol of CaCO₃/100 g)
number of moles = 0.2 moles of CaCO₃

<em>Answer: 0.2 moles</em>

6 0

3 years ago

25. How many ml of a .0023M strontium hydroxide solution are needed to completely react 15.0 mL of 0.012M hydrochloric acid?

Mariana [72]

Answer: There are 78.26 mL of a 0.0023M strontium hydroxide solution are needed to completely react 15.0 mL of 0.012M hydrochloric acid.

Explanation:

Given: $M_{1}$ = 0.0023 M, $V_{1}$ = ?

$V_{2}$ = 15.0 mL, $M_{2}$ = 0.012 M

Formula used to calculate volume of strontium hydroxide solution is as follows.

$M_{1}V_{1} = M_{2}V_{2}$

Substitute the values into above formula as follows.

$M_{1}V_{1} = M_{2}V_{2}\\0.0023 M \times V_{1} = 0.012 M \times 15.0 mL\\V_{1} = 78.26 mL$

Thus, we can conclude that there are 78.26 mL of a 0.0023M strontium hydroxide solution are needed to completely react 15.0 mL of 0.012M hydrochloric acid.

8 0

3 years ago

David pushes the wall to the left with his finger. The

Kruka [31]

Answer:

push or pull

Explanation:

3 0

2 years ago