How many grams of H2O are needed to produce 150. g of Mg(OH)2? Mg3N2(s) + 6H2O(l) → 3Mg(OH)2(aq) + 2NH3(g)

About 92.67 grams of H2O are required

Explanation:

The easier way for some people is to work backwards.

Since we already have the amount of grams produced (for Mg(OH)2), we can just start from there.

In order to find the amount of grams of H2O needed we need to know the amount of moles actually used in the chemical reaction.

We can find this using the balanced chemical equation to convert from grams of Magnesium Hydroxide to moles of Magnesium Hydroxide to moles of Water and finally to grams of Water.

**58.319 g is the amu (molar mass) of Mg(OH)2

Step 1 ->  150 g Mg(OH)2 *  = 2.572060563 moles

We can round that to 2.572 moles of Mg(OH)2 produced.

Step 2 -> Now we can convert from moles of Mg(OH)2 to moles of H2O

We will do this using the balanced chemical equation

2.572 moles Mg(OH)2 * = 5.144 moles of H2O required

Step 3 -> Now we will convert from moles of H2O (water) to grams

**Using the amu (molecular mass)

The molecular mass of water is about 18.015 grams

5.144 moles * = 92.66916 grams of H2O

So, about 92.67 grams of H2O are required

hey there!

mass = 6.75 g

volume =   9 cm³

therefore:

d = mass / volume

d   = 6.75 / 9

d = 0.7 g/cm³

answer b