Dj Tan

University of Wisconsin - Madison
Teacher

Biography

I worked as lecturer in many Engineering courses and tutored students in premier universities in STEM in the country

Education

BS Physics
University of Wisconsin - Madison

Educator Statistics

Numerade tutor for 5 years
4760 Students Helped

Topics Covered

Mastering Chemical Reactions and Stoichiometry for Optimal Results
Understanding Electronic Structure: A Comprehensive Guide
Differential Equations Made Simple: Expert Tips & Resources

DJ's Textbook Answer Videos

07:12
Differential Equations

A certain chemical is converted into another chemical by a chemical reaction. The rate at which the first chemical is converted is proportional to the amount of this chemical present at any instant. Ten percent of the original amount of the first chemical has been converted in 5 min.
(a) What percent of the first chemical will have been converted in 20 min?
(b) In how many minutes will $60 \%$ of the first chemical have been converted?

Chapter 3: Applications of First-Order Equations
Section 3: Rate Problems
Dj Tan
08:16
Differential Equations

A chemical reaction converts a certain chemical into another chemical, and the rate at which the first chemical is converted is proportional to the amount of this chemical present at any time. At the end of one hour, $50 \mathrm{gm}$ of the first chemical remain; while at the end of three hours, only $25 \mathrm{gm}$ remain.
(a) How many grams of the first chemical were present initially?
(b) How many grams of the first chemical will remain at the end of five hours?
(c) In how many hours will only $2 \mathrm{gm}$ of the first chemical remain?

Chapter 3: Applications of First-Order Equations
Section 3: Rate Problems
Dj Tan
06:48
Differential Equations

A chemical reaction converts a certain chemical into another chemical, and the rate at which the first chemical is converted is proportional to the amount of this chemical present at any time. At the end of one hour, two-thirds $\mathrm{kg}$ of the first chemical remains, while at the end of four hours, only one-third $\mathrm{kg}$ remains.
(a) What fraction of the first chemical remains at the end of seven hours?
(b) When will only one-tenth of the first chemical remain?

Chapter 3: Applications of First-Order Equations
Section 3: Rate Problems
Dj Tan
05:27
Differential Equations

Assume that the population of a certain city increases at a rate proportional to the number of inhabitants at any time. If the population doubles in 40 years, in how many years will it triple?

Chapter 3: Applications of First-Order Equations
Section 3: Rate Problems
Dj Tan
05:21
Differential Equations

The population of the city of Bingville increases at a rate proportional to the number of its inhabitants present at any time $t$. If the population of Bingville was 30,000 in 1970 and 35,000 in 1980 , what will be the population of Bingville in $1990 ?$

Chapter 3: Applications of First-Order Equations
Section 3: Rate Problems
Dj Tan
1 2

DJ's Quick Ask Videos

01:21
Chemistry 101

Ammonia (NH3) can be synthesized from nitrogen gas (N2) and hydrogen gas (H2) by the following reaction.
N2(g) + 3 H2(g) ? 2 NH3(g)
If the theoretical yield of ammonia is 357 g and the actual yield is 231 g, calculate the percent yield of ammonia.

Dj Tan
01:30
Chemistry 101

What is the molarity of a sucrose solution that contains 17.0 g of C12H22O11 (342.34 g/mol) dissolved in 122.0 mL of solution?
Show work step-by-step and circle or bold answer.

Dj Tan
07:45
Chemistry 101

If 17.3 kg of Al2O3(s), 51.4 kg
of NaOH(l), and 51.4 kg of HF(g) react
completely, how many kilograms of cryolite will
be produced?
b) Which reactants will be in excess?
c)What is the total mass of the excess reactants left over after
the reaction is complete?

Dj Tan
03:55
Chemistry 101

Compare 1 mole of N2, 1 mole of H2, and 1 mole of Cl2. *
a. Which has the greatest number of molecules? Why?
b. Which has the smallest mass? Why?

Dj Tan
02:53
Chemistry 101

How many molecules are contained in each of the following number
of moles?
Report your answer using two significant figures.
a. 5.1 mol of penicillin molecules
b. 0.89 mol of NH3 molecules
a. Ă—
10 molecules
b.
Ă— 10 molecules

Dj Tan
03:28
Chemistry 101

While performing a Thermite reaction, 56 kg of molten iron was obtained from the reaction of 32 kg of aluminum powder with excess iron(III) oxide. What is the percentage yield and percent difference of iron in this reaction?

Dj Tan
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