57.0 mL of 3.40 M sodium hydroxide is combined with 38.0 mL of 1.90 M magnesium chloride. What mass in grams of solid forms?

4.06 g of Mg(OH)2

Explanation:

The equation of the reaction is;

2NaOH(aq) + MgCl2(aq) > Mg(OH)2(s) + 2NaCl(aq)

Number of moles of NaOH= 57/1000 * 3.40 = 0.19 moles

Number of moles of MgCl2 = 38/1000 * 1.9 = 0.07 moles

We must find the limiting reactant. This is the reactant that yields the least amount of the solid.

From the reaction equation;

2 moles of NaOH yields 1 mole of Mg(OH)2

0.19 moles of NaOH yields 0.19 * 1/2 = 0.095 moles of Mg(OH)2

Also;

1 mole of MgCl2 yields 1 mole of Mg(OH)2

0.07 moles of MgCl2 also yields 0.07 moles of Mg(OH)2

Hence MgCl2 is the limiting reactant and 0.07 moles of Mg(OH)2 is produced.

Mass of Mg(OH)2 produced = number of mole * molar mass

molar mass of Mg(OH)2 = 58 g/mol

Mass of Mg(OH)2 produced = 0.07mol * 58 g/mol = 4.06 g of Mg(OH)2

for step 7 table c on the lab "newtons law of action"   the average time it took the car to travel .25 meters   was 1.92 seconds.

the average time it took the car to travel 0.50 meters was 2.61 seconds

hope this : )