Respuesta :
Answer:
You need to measure 120.9132 grams of MgO and add to 1 liter of distilled water in a beaker.
Explanation:
Capital M stands for molarity, or moles/liter. So 3 M MgO means 3 moles per liter of MgO.
1 L × [tex]\frac{3 moles MgO}{1 L MgO}[/tex] = 3 moles MgO
This means you need to measure 3 moles MgO to put into 1 Liter of water.
But you don't know how much that is, so you need to convert moles to grams.
First you need to find how many grams are in 1 mole of MgO.
You can search the molar mass of MgO online to get: 40.3044 g
But if you don't have the internet, use the periodic table to add the masses of Mg and O: 24.305 g + 15.999 g = 40.3044 g
Then write the fraction so that the units cancel out, so you get grams by itself on the top of the fraction.
1 L × [tex]\frac{3 moles MgO}{1 L MgO}[/tex] × [tex]\frac{40.3044 g MgO}{1 mole MgO}[/tex] = 120.9132 g MgO
You need to measure 120.9132 grams of MgO and add to 1 liter of distilled water.
We will prepare 1 L solution of 3 M MgO, by dissolving 120.91 grams of MgO in 1 litre of water.
How molarity is define?
Molarity is define as the no. of moles of solute dissolve in per liter if solvent or solution & it is represented as:
M = n / v
In the question, it is given that:
Molarity of MgO = 3M i.e. 3 moles of MgO is present in 1 liter of solution.
So, we have moles of MgO = 3 moles
Now, we convert moles of MgO to grams to know how much of solute is required, in the following manner:
n = W / M, where
M = molar mass of MgO = 40.30 g/mole
W = to find?
W = 3 mole × 40.30 g/mole = 120.91 grams
Hence, 120.91 grams of MgO is required.
To know more about molarity, visit the below link:
https://brainly.com/question/14469428
