One kilogram of Refrigerant 134a contained within a piston-cylinder assembly undergoes a process from a state where the pressure is 7 bar and the quality is $50 \%$ to a state where the temperature is $16^{\circ} \mathrm{C}$ and the refrigerant is saturated liquid. Find the change in specific entropy of the refrigerant, in $\mathrm{kJ} / \mathrm{kg} \cdot \mathrm{K}$. Can this process be accomplished adiabatically?

A study of climbers who reached the summit of Mount Everest without supplemental oxygen showed that the partial pressures of $O _2$ and $CO _2$ in their lungs were 35 $mm Hg$ and $7.5 mm Hg$, respectively. The barometric pressure at the summit was $253 mm Hg$. Assume the lung gases are saturated with moisture at a body temperature of $37{ }^{\circ} C$ [which means the partial pressure of water vapor in the lungs is $P\left( H _2 O \right)=47.1 mm Hg$ ]. If you assume the lung gases consist of only $O _2, N _2, CO _2$, and $H _2 O$, what is the partial pressure of $N _2$?

The key process in a blast furnace during the production of iron is the reaction of $\mathrm{Fe}_2 \mathrm{O}_3$ and carbon to yield $\mathrm{Fe}$ and $\mathrm{CO}_2$.
(b) Is the reaction spontaneous at low or at high $T$ ? Explain.

A mass of 0.2 kg of saturated refrigerant-134a is contained in a piston-cylinder device at 200 kPa. Initially, 75 oercent of the mass is in the liquid phase. Now heat is transferred to the refrigerant at constant pressure until the cylinder contains vapor only. Show the process on a $P-v$ diagram with respect to saturation lines. Determine (a) the volume occupied by the refrigerant initially, (b) the work done, and (c) the total heat transfer.

Lorenzo Company applies overhead to jobs on the basis of direct materials cost. At year-end, the Work in Process Inventory account shows the following.

1. Determine the predetermined overhead rate used (based on direct materials cost).
2. Only one job remained in work in process inventory at December 31. Its direct materials cost is $30,000. How much direct labor cost and overhead cost are assigned to this job?

The weight of an object on an orbiting space vehicle is estimated to be $42 \mathrm{~N}$ based on an artificial gravitational acceleration of $6 \mathrm{~m} / \mathrm{s}^2$. What is the weight of the object, in $\mathrm{N}$, on earth, where $g=9.81 \mathrm{~m} / \mathrm{s}^2$ ?

Which is a property of acidic solutions? A They taste sour. B They feel slippery. C They are in many cleaning products. D They taste bitter.

In this exercise, find, to the nearest degree, the measure of the angle of the triangle with the given measures of the sides.

12, 20, 22

a. The IR spectra portrayed contain a sharp absorption at approximately $3500 \mathrm{~cm}^{-1}$. Specify the functional group responsible.
b. Both of these spectra have complex absorptions in the range of $3100-3400$ $\mathrm{cm}^{-1}$. What functional group is responsible?
c. What functionality is responsible for the absorption near $1700 \mathrm{~cm}^{-1}$ ?

You will use a CAS to identify the local extrema of the function. Perform the following steps:
(a) Plot the function over the given rectangle. (b) Plot some level curves in the rectangle. (c) Calculate the function's first partial derivatives and find the critical points. How do the critical points relate to the level curves plotted in (b)? Which critical points, if any, appear to give a saddle point? Give reasons for your answer.
$f(x, y)=2 x^4+y^4-2 x^2-2 y^2+3, \quad-3 / 2 \leq x \leq 3 / 2$, $-3 / 2 \leq y \leq 3 / 2$

In this exercise, solve the first-order linear differential equation.

$$y^{\prime}-y=10$$

What is the acceleration due to gravity on Jupiter if someone who weighs $600 \mathrm{~N}$ on Earth weighs $1400 \mathrm{~N}$ on Jupiter?
A. $26 \mathrm{~m} / \mathrm{s}^2$
B. $19 \mathrm{~m} / \mathrm{s}^2$
C. $21 \mathrm{~m} / \mathrm{s}^2$
D. $23 \mathrm{~m} / \mathrm{s}^2$

A sealed rigid vessel has volume of 1 m3 and contains 2 kg of water at 100$^{\circ} \mathrm{C}$. The vessel is now heated. If a safety pressure valve is installed, at what pressure should the valve be set to have a maximum temperature of 200$^{\circ} \mathrm{C}$?

Water contained in a piston–cylinder assembly, initially at $300^{\circ} \mathrm{F}$, a quality of 90$\%$, and a volume of 6 $\text{ft}^{3}$, is heated at constant temperature to saturated vapor. If the rate of heat transfer is 0.3 Btu/s, determine the time, in min, for this process of the water to occur. Kinetic and potential energy effects are negligible.