GradePack

    • Home
    • Blog
Skip to content
bg
bg
bg
bg

GradePack

14. A phase diagram for a substance with a molar mass of 60….

14. A phase diagram for a substance with a molar mass of 60.1 g/mol is shown below. (WCSP[x]) a. (6 points) Sketch the heating curve for the substance going from -30 °C to 150 °C (point A to point B on the diagram above).  A template is given below. b. (6 points) Calculate the heat required to vaporize 30 g of the substance initially at room temperature (25 ºC). (WCSP[x]) ΔHfus 5.4 kJ/mol ΔHvap 45.1 kJ/mol Cs (solid) 2.45 J/g°C Cs (liquid) 2.26 J/g°C Cs (gas) 2.05 J/g°C Melting point -89.5 °C Boiling point 82.6 °C   Enter the value in the box below.   

Read Details

6.  You have likely heard of the weed killer Round Up.  It i…

6.  You have likely heard of the weed killer Round Up.  It is a solution of glyphosate in water.   To prepare a solution for application, you need to do a dilution of the concentrate so that the final concentration of glyphosate is 0.45 M (equivalent to a 5% glyphosate). Calculate the volume of 2.8 M Round Up concentrate needed to make 1 gallon (3.875 L) of 0.45 M weed killer for yard and garden application. (WCSP[x], 6 points) Enter the value in the box below.   

Read Details

4.  (WCSP24.[x], 8 points) Cell phones use electromagnetic r…

4.  (WCSP24.[x], 8 points) Cell phones use electromagnetic radiation with an energy of about 1.08 J/mol of photons.   Calculate the wavelength (in nm) and frequency that can be used to describe light with this energy. Enter the wavelength in nm below.

Read Details

16. Carbon monoxide is a toxic gas.  The upper limit of carb…

16. Carbon monoxide is a toxic gas.  The upper limit of carbon monoxide (CO) in air is 9 ppm (9.0 x 10-6) over an 8-hour period.  a. At this concentration, how many moles of CO are there in a bedroom with a volume of 29,000 L at 25 oC and 0.98 atm? (3 points, WCSP[x]) b. How many molecules of CO are in the room? (3 points, WCSP[x])   Enter the value from part a in the box below.   

Read Details

5.  Ice cream begins as a solution of milk, sugar, and stabi…

5.  Ice cream begins as a solution of milk, sugar, and stabilizers. This liquid mixture is pasteurized at high temperature (72 oC) to kill any harmful bacteria. The pasteurized solution is cooled, flavors are added, and then it is placed in a “hardening room” (at -38 oC) to freeze.   Cs (solid) = 3.10 J/g·K Cs (liquid) = 1.60 J/g·K ΔHfus = 186 J/g a. (WCSP24.[x], 5 points) Draw the cooling curve for ice cream beginning as a liquid at 72 oC to solid at -38 oC. The freezing point of ice cream is -3 oC.  Label the axes with temperature values. (Blank graph given below.))   b.  (WCSP24.[x], 8 points) Calculate how much heat (in kJ) must be removed from a ½ gallon (912 g) of Bittersweet Mint when it cools from 72 oC to -38 oC.   Enter the heat lost from the ice cream below:

Read Details

10.  (WCSP24.[x]) Hot air is less dense than cold air and th…

10.  (WCSP24.[x]) Hot air is less dense than cold air and this is the reason that hot air balloons float! A hot air balloon on a cool summer morning is filled with air to a volume of 2.20 x 106 L and warmed to 195 °F (90 °C).  A hot air balloon must be inflated to a volume of approximately 2.60 x 106  L in order to float in air. a. (4 points) At constant pressure, provide a molecular-level explanation of the relationship between temperature and volume of a gas.   b.  (6 points) Calculate the temperature the gas must be (in °C) in order to float.   Enter the temperature below

Read Details

6. Scuba divers breathe a specialized mixture of gases so th…

6. Scuba divers breathe a specialized mixture of gases so the concentration of dissolved oxygen in the blood stream does not reach toxic levels. A 12.5-L scuba diving tank contains a helium-oxygen (heliox) mixture of 24.2 g of He and 4.32 g of O2 at 25 oC. (WCSP24.[x]) a. (6 points) What is the mole fraction of O2 in the tank? b. (6 points) What is the partial pressure of O2 in the tank?   Enter the partial pressure of oxygen in the tank below:

Read Details

Suppose we add the following variations to the edges. In whi…

Suppose we add the following variations to the edges. In which cases is the MST of the original graph still a MST of the updated graph?

Read Details

You attended the delivery of monochorionic twins who were bo…

You attended the delivery of monochorionic twins who were born at 33 weeks gestation.  One of the twins appeared much paler than then other twin in the delivery and so you ordered CBCs on both of them. Twin A had a hemoglobin level of 19.5 and twin B had a hemoglobin level of 10.2 with a retic count of 5%. Your diagnosis is:

Read Details

An infant who is born with a birth weight of 4200grams is cl…

An infant who is born with a birth weight of 4200grams is classified as _______.

Read Details

Posts pagination

Newer posts 1 … 34,981 34,982 34,983 34,984 34,985 … 80,332 Older posts

GradePack

  • Privacy Policy
  • Terms of Service
Top