Air enters a counterflow heat exchanger operating at steady state at 22°C, 0.1 MPa and exits at 7°C. Refrigerant 134a enters at 0.2 MPa, a quality of 0.33, and a mass flow rate of 30 kg/h. Refrigerant exits at 0°C. There is no significant change in pressure for either stream.

Let T₀ = 22°C, p₀ = 0.1 MPa, and ignore the effects of motion and gravity.
Round your answers to 3 significant digits.

You purchase an expensive O2 microelectrode and use it to measure the dissolved O2 profile in a sediment core that you obtained from Long Island Sound. You find that the O2 concentration on the water-sediment interface is 240 mol/L, and it sharply drops to 40 mol/L at 0.2 cm deep in the sediment. If the corresponding dissolved O2 diffusion coefficient (Ds) in porewater seawater is 1.0 × 10-5 cm2 /s. The porosity () of sediment is approximately constant over the sampled interval with  = 0.9. Calculate the diffusive flux of O2 across the sediment – water interface assuming Fick’s First Law of diffusion for porous media in 1-dimension. Make sure that you indicate the sign of the flux (into or out of the sediment).

The working range of the total phenol test is 0-5.00 mg/L. You have at your disposal multiple 500 ± 0.2 mL and 100 ± 0.15 mL volumetric flasks for calibration standard preparation, a 2L Winchester of 99.95% phenol, unlimited distilled/deionized water, and standard 5 ± 0.015, 10 ± 0.025, 25 ± 0.05 mL pipettes:

question : Propose a methodology to produce a stock solution of ~ 5.00 mg/L (ρ(phenol) = 1.07 g/cm³) and the dilution steps taken to produce 6x calibration standards (~ 0, 1, 2, 3, 4, 5 mg/L pure phenol in solution). Determine the concentration of your standards with errors (Graduate Capability - Quantitative literacy)

You are out fishing, when you go to reach for the cooler, when you clumsily knock it into the water. The cooler is in the shape of a cube with a side-length 0.2 meters. The cooler plus sandwiches inside weigh 6 pounds (26.7 N).

a) How deep below the water's surface is the bottom of the cooler, assuming it floats stationary with the top and bottom level with the water's surface?

b) When the cooler was just sitting on the boat, there was actually a buoyant force on it from air. How big is the buoyant force of air on the cooler? How many times smaller is that force than the weight of the cooler? Assume you are at sea level where the density of air is 1.225 kg/m^3

Brady is a figure skater. He finds a few of the jumps he does to be difficult, but the rest are easy for him. He must include four jumps in his routine. He always makes the first jump a difficult one. After a difficult jump, there is a 0.4 probability that he'll do another difficult jump, and otherwise he'll do an easy one. After an easy jump, there is a 0.2 probability that he'll do another easy one, and otherwise he'll do a hard one.  

What is the probability that the final (fourth) jump of his routine will be an easy one?    

What is the probability that all four jumps of his routine will be difficult ones?    
Enter your answers as whole numbers or decimals.

Mulitple Choice please answer all 3 no need to go in Depth

One mole (mol) of glucose (molecular mass = 180 daltons) is.

If the pH of a certain soda drink is 2, what is the hydrogen ion concentration in that drink?

Which chemical group is most likely responsible for an organic molecule behaving as a base?

Principles of Macroeconomics

Consider two economies (US and CAN) that begin in steady state. The two countries are identical. The production function is:

? = ?? + ?

Suppose the following parameter values:

? = 1, ? = 0.1, ? = 0.2, ? = 1000

Then, a strong earthquake destroys 90% the steady state physical capital in CAN and 10% the steady state physical capital in US.

Assume these new levels of steady state physical capital become the starting levels of capital for each economy at period 0: ?₀.

Find the growth rate of output for each economy between the periods 0 and 1. Do you observe the catch-up effect (Mankiw, Chapter 12) in this case? Explain in terms of the level of output and its corresponding growth rate.

Consider the following daily time series representing the number of clients visiting the Small Business Development Center over the previous 10 days.

Step 1 of 2: What is the Simple Exponential Smoothing Forecast for day 11 (t = 11) assuming that the smoothing constant, alpha = 0.2?
Round to 2 decimal places.

Step 2 of 2: What is the Simple Exponential Smoothing Forecast for day 11 (t = 11) assuming that the smoothing constant, alpha = 0.75?
Round to 2 decimal places.

1.) How many milligrams of sodium chloride should be used in compounding the prescription?

*Type in your answer to 2 decimal places. Do not forget the unit

2.)

How many milliliters of a 0.9% solution of NaCl should be used to prepare the prescription?

*Type in your answer to 2 decimal places. Do not forget the unit

Discrete random variables X and Y have joint probability mass function defined by the table below.

X= { 0 , 1 , 2 } , Y= { − 2 , 0 , 2 }   

A.) Evaluate the expected value of X (round to 2 decimal digits)

B.) Evaluate the variance of X (round to 2 decimal digits)

C.) Evaluate the covariance of X and Y. (round to 2 decimal digits) Are X and Y independent?

D.) Let W=3X-2Y+4. What is the mean of W? What is the standard deviation of W? (round to 2 decimal digits)