# Posts by Tan

Total # Posts: 40

**Chemistry**

In a qualitative analysis, the test for the presence of Cu^2+ ion is the formation of the bright blue complex ion Cu(NH3)42+. What is the equilibrium concentration of Cu2+ when 1.0 mL of 0.200 M Cu^2+ is combined with 1.0 mL of 15.0 M NH3? (Kf Cu(NH3)4^2+ = 5.0 x 10^12).

**Math**

Standing 4ft from the mirror lying on the ground ground, Palmer who's eye height is 5ft 9inches, can reflection the top of the tree. He measures the mirror to be 24ft from the tree. How tall is the tree?

**Math**

In 1924, the temperature in Fairfield, Montana, dropped from 63 degrees to -21 degrees in 12 hours. What was the average hourly change in temperature. Thank you

**Math**

A ribbon is 12 3/8 feet long. Into how many 3/4 -foot pieces can it be cut?

**Math**

Juana paid $1,200 for a sofa. The price of the sofa Ben purchased was 3/5 the price that Juana paid. How much did Ben pay for his sofa?

**Math**

Jared bought a cell phone for $42. Juanita spent 1 1/2 times as much. How much did she spend? Thank you very much!

**Physics**

The driver of a sport car pushed down the accelerator so that the engine pushes the care forward with a force of 2500N,s tarting from rest. How fast the car can go after 20s later? I have tried this by using v=u+at but i don't have a. From F=ma, i cant get the value of a ...

**Science chemistry**

Which compound has the melting point of -23 degree Celsius and boiling point of 77 degree Celsius ? Thx....

**physics**

As shown in the figure, a bullet of mass m and speed v passes completely through a pendulum bob of mass M. The bullet emerges with a speed of v/2. The pendulum bob is suspended by a stiff rod of length ℓ and negligible mass. 2.1 Derive an expression for the minimum value...

**Science**

Acetylene gas combust.how many grams of carbon dioxide and grams of water are produced when 52.0 g of acetylene burns ?

**Chemistry**

An unknown mass of caco3 was added to an excess of 2mol/dm3 hcl. Calculate the total volume of co2 evolved.

**Fianance**

A tax-exempt bond was recently issued at an annual 8 percent coupon rate and matures 20 years from today. The par value of the bond is $1,000.

**MATH**

Thank you Steve :)

**MATH**

You would like to construct a 400-square-foot rectangular garden along your driveway. The fencing on the driveway side costs $15 per linear foot, while the fencing for the other three sides costs $8 per linear foot. Write an expression for the cost of the enclosed rectangular ...

**math**

Solve the equation 4x^3 + 32x^2 + 79x + 60 =0 given that the root is equal to the sum of the other two roots. (Hint: set roots as alpha, beta, gamma)

**Math**

A car engine is running at 5000 revolutions per minute. (a) how many revolutions are made in one hour? (b)if this engine uses 10 litres of fuel in one hour, how much fuel, in millilitres,does it use for every revolution?

**math**

WHAT ARE THE QUESTION IN BUSMATH?

**Chemistry**

When 0.100 mol CaCO3(s) and 0.100 mol CaO(s) are placed in an evacuated sealed 10.0 L container and heated to 385 K, P(CO2) = 0.220 atm after equilibrium is established. CaCO3(s) <~> CaO(s) + CO2(g) 0.05 atm CO2(g) is then removed from the container. What is the total ...

**6th grade**

Pet Parade: Mr. James has 14 cats, dogs and guinea pigs. What are all the combinations he could have?

**chemistry**

what's the discussion for determine BaCl2.2H2O in lab report

**calculus**

i don't understand this part:dt/(t^2 + 1) = (1/2)ln(t^2 + 1)

**calculus**

assume that during the first 3 minutes after a foreign substance is introduced into the blood,the rate R'(t) at which new antibodies are produced(in thousands of antibodies per minute) is given by R'(t)=t/(t^2+1) where t is in minutes.find the total quantity of new ...

**Math**

Last semester, a certain professor gave 36 As out of 390 grades. If one of the professor's students from last semester were selected randomly, what is the probability that student received an A? (Assume that each student receives one grade.)

**Physics**

a 2 centimeter diameter ball of 50 grams rolls at constant velocity across a table. it takes 4 seconds to travel 3 meters. Sketch graph of horizontal position, velocity and acceleration.

**math**

Write a quadractic equation having given equations? -9,9i

**Ap World**

what does colonial legacy mean?

**Physics**

-2.3i+4.5j

**ACCT**

The question is: In the journal provided, prepare year- end adjustments for the following situations. Omit explanations. a. accrued interest on notes receivable is $105 b. of the $12,000 received in advance of earning a service, one third was still unearned by year end. c. ...

**english**

Would Culture, Heroism, and Supernatural Forces in Beowulf be a good topic for an expository essay on Beowulf being an epic poem?

**math**

0.45

**math**

Consider that the age, x, of a unicorn in human equivalent years can be given by the formula f(x) = - 0.001618x4 + 0.057326x3 – 1.1367x2 + 11.46x + 2.914. When a unicorn is 2.5 years old, what is its age in human equivalent years? What about when it is 12 years old?

**probability**

1. The time it takes a student to cycle to school is normally distributed with a mean of 15 minutes and a variance of 2. The student has to be at school at 8.00a.m. At what time should the student leave her house so that she will be late only 4% of the time? 2. In a study for ...

**geometry (high school)**

if there are two tangent circles that have two external tangent lines that intersect at a 60 degree angle, what is the ratio of the radii.

**Math homework**

when given 5,5,5,5,5 using the order of operations and parenthesesto make a true expression where would i place my -,+ *,/ to make the answer equal 1

**Geometry**

Hi, I have to use algebra to find the coordinates of the point where two lines intersect, the first line passes through the points 4,3 and 10,0 and the second line is y=6. Any ideas would be very much appreciated, many thanks

**Math/modelling**

Hi, I have a linear model with equation p =5.1t - 28, which concerns breeding pairs of birds where p is the number of breeding pairs and t is the year. I need to use this model to estimate the number of breeding pairs in year 15. I would assume to do this I just need to insert...

**Algebra**

Could someone tell me the solution for x^2 - 3x = 0, i know x = 3 but I just need to know how to get there please

**physics**

what would be the significance of the photoelectric effect graph if it a) passed through the origin b) had a positive y intercept

**english**

how to write instructions for turning someone into a toad

**math**

When two digits of thbase 10 representation of an inteer are intercharged, the diference bewen the old number and the new number is divisible by 9. Why? What happens in other bases? 10A + B - 10B -A= difference. This reduces to 9A - 9B 9(A-b)= difference. Of course it is ...