Answer:
C
Explanation:
Only this choice is applicable and correct.
The inter-molecular forces of attraction between the molecules must have been broken (overcome) before the molecules can gain an increase in the kinetic energies between them.
Answer:
89.34%
Explanation:
First, write a balanced reaction.
Mg3N2 + <u>6</u>H2O --> <u>3</u>Mg (OH)2 + <u>2</u>NH3
Next determine the moles of the known substance, or limiting reagent ( H2O)
n= m/MM
n ( H2O) = 4.33/(1.008×2)+16
n(H2O)= 0.2403
Use the mole ratio to find the moles of Mg(OH)2
0.2403 ÷2
n (Mg (OH)2) = 0.1202
Next, find the theoretical mass of Mg (OH)2 that should have been produced
m= n × MM
m= 0.1202 × (24.305 + (16×2) +(1.008 ×2))
=7.007g
To find percentage yield, divide the experimental amount by the theoretical amount and multiply by 100.
6.26/ 7.007 × 100
=89.34%
Answer:
molecular mass of each substance
molecular mass of each substance
Explanation:
Answer:
760 uM
Explanation:
<em>A biochemist carefully measures the molarity of magnesium ion in 47, mL of cell growth medium to be 97 uM. Unfortunately, a careless graduate student forgets to cover the container of growth medium and a substantial amount of the solvent evaporates. The volume of the cell growth medium falls to 6.0 mL. Calculate the new molarity of magnesium ion in the cell growth medium Be sure your answer has the correct number of significant digits.</em>
The problem here is that the amount of magnesium ion remains the same irrespective of the volume.
Amount of magnesium in the growth medium = <em>molarity x volume</em>
= 97 x x 47 x = 4.559 x
Then, the volume reduced to 6.0 mL, the new molarity becomes;
<em>molarity = mole/volume </em>
= 4.559 x /6 x = 7.598333 x M = 759.83333 uM
To the correct number of significant digits = 760 uM
You have 0.50 mol of NH3 and 0.20 mol of NH4+ to start (NH4Cl dissolves completely), given the molarity and 1.0 L solution.
30.0 mL of 1.0 M HCl is 0.0300 mol of HCl. This will react with the NH3 to produced 0.030 mol of NH4+.
You now have 0.47 mol NH3 and 0.23 mol NH4+. Now use the Henderson-Hasselbach equation to calculate your pH. The equation says to use concentration of acid and base, but you can just use the moles of them because it doesn’t make a difference.
pH = pKa + log(base/acid)
pKa = 14 - pKb = 14 - 4.75 = 9.25
pH = 9.25 + log(0.47/0.23) = 9.56