The official web site of the Nobel Prize explains that Marie Curie’s chemistry prize was partly for her discovery that the radio
2 answers:
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Answer:
2.02 g
Explanation:
Molality (m) is the <em>number of moles of solute dissolved in 1 kg (1000 g) of solvent- </em>that is,
<em> </em>
Our first step is to calculate the moles of NH₃ in 475 grams of methanol, using <u>molality</u> as a conversion factor.
0.250 mol/kg × 0.475 kg = 0.119 mol
This solution contains <u>0.119 moles of NH₃</u>. Now we must convert the moles to grams, using the <u>molar mass of NH₃</u> as a conversion factor .
17.031 g/mol × 0.119 mol = 2.02 g
Therefore, 2.02 grams of NH₃ must be dissolved in 475 grams of methanol to make a 0.250 m solution.
Complete question:
The decomposition of SO2Cl2 is first order in SO2Cl2 and has a rate constant of 1.44×10⁻⁴ s⁻¹ at a certain temperature.
If the initial concentration of SO2Cl2 is 0.125 M , what is the concentration of SO2Cl2 after 210 s ?
Answer:
After 210 s the concentration of SO2Cl2 will be 0.121 M
Explanation:
where;
At is the concentration of A at a time t
A₀ is the initial concentration of A
k is rate constant = 1.44×10⁻⁴ s⁻¹
t is time
ln(At/A₀) = -( 1.44×10⁻⁴)t
ln(At/0.125) = -( 1.44×10⁻⁴)210
ln(At/0.125) = -0.03024
At/0.125 = 0.9702
At = 0.125*0.9702
At = 0.121 M
Therefore, after 210 s the concentration of SO2Cl2 will be 0.121 M