Answer:
94.4g/mol is molar mass of the unknown
Explanation:
Based on the freezing point depression equation:
ΔT = Kf*m*i
<em>Where ΔT is the depression in freezing point (1.87°C)</em>
<em>Kf is freezing point depression constant of water (1.86°Ckg/mol)</em>
<em>And i is Van't Hoff factor (1 for nonelectrolyte solutes)</em>
<em />
Replacing:
1.87°C = 1.86°CKg/mol*m*i
1.005mol/kg solvent = m
Using the mass of the solvent we can find the oles of the nonelectrolyte:
1.005mol/kg solvent * 0.4764kg = 0.479moles
Molar mass is defined as the ratio between mass of a substance in grams and moles, that is:
45.2g / 0.479mol =
<h3>94.4g/mol is molar mass of the unknown</h3>
The half-life of the substance is 3.106 years.
<h3>What is the formula for exponential decay?</h3>
- The exponential decline, which is a rapid reduction over time, can be calculated with the use of the exponential decay formula.
- The exponential decay formula is used to determine population decay, half-life, radioactivity decay, and other phenomena.
- The general form is F(x) = a.
Here,
a = the initial amount of substance
1-r is the decay rate
x = time span
The equation is given in its correct form as follows:
a =
×
As this is an exponential decay of a first order reaction, t is an exponent of 0.8.
Now let's figure out the half life. Since the amount left is half of the initial amount at time t, that is when:
a = 0.5 a0
<h3>Substituting this into the equation:</h3>
0.5
=
×
0.5 = 
taking log on both sides
t log 0.8 = log 0.5
t = log 0.5/log 0.8
t = 3.106 years
The half-life of the substance is 3.106 years.
To learn more about exponential decay formula visit:
brainly.com/question/28172854
#SPJ4
It is an open circuit because the metal does not complete the electric flow