Quiz 8 (solutions & energy)

If 100.0 mL of 0.426M NaOH solution is diluted by adding 400.0 mL of water, what is the concentration of the diluted solution?

0.0852M

If 100.0 mL of a 0.426M NaOH solution is diluted to 500.0 mL, what is the new concentration of the diluted solution?

0.0852M

What is the osmols of a 0.02M Al2(SO4)3 solution?

0.1 osmols

which has the most number of moles of HCl -0.04L of a 0.1M HCl -0.01L of a 0.5M HCl -0.2L of a 0.2M HCl

0.2L of a 0.2M HCl

Which would have the highest osmotic pressure? - 0.2M Al(NO3)3 - 0.2M KCl - 0.2M glucose - 0.2M (NH4)2CO3

0.2M Al(NO3)3

Which would have the lowest osmotic pressure? - 0.2M Al(NO3)3 - 0.2M KCl - 0.2M glucose - 0.2M (NH4)2CO3

0.2M KCl

Magnesium hydroxide can be made in the reaction; MgCl2 + 2NaOH Mg(OH)2 + 2NaCl. If a chemist needs 0.725 moles of NaOH for this reaction, what volume of a 1.50M NaOH solution is needed?

0.483 liters

What is the molarity of a solution if 300.0 mL of it contains 16.8 grams of KNO3?

0.554M

How many liters of a 2.25 M CH2O solution can be prepared from 1.75 moles of the solute?

0.778

In order to prepare a 0.0500M NaOH solution, to what volume would you dilute 25.0 mL of 2.50M NaOH?

1.25 liters

which is the most concentrated solution - 40 mL of a 0.1M HCl - 10 mL of a 0.5M HCl - 200 mL of a 0.2M HCL

10 mL of a 0.5M HCl

what is the delta H?

25 KJ

How many milliliters of a 0.1250M KCl solution contains 2.330 grams of KCl?

250.0 mL

How many grams are needed to prepare 375 mL of a 0.600 M solution of Ba(OH)2?

38.5 grams

A student needs to prepare 250.0 mL of a 2.50M HCl solution using the stock solution 12.0M HCl. What volume of the 12.0M HCl is needed for the dilution?

52.1 mL

What is the osmols of a 2.0 x 10-2 M Na3PO4 solution?

8.0 x 10^-2 osmols

Which letter represents the activation energy of the reaction?

A

Which of the following is necessary for a chemical reaction to occur between two reactants (A and B)?

A and B must collide with sufficient energy and the proper orientation

Why does the rate of a chemical reaction increase with temperature?

At higher temperatures, reactant molecules move faster, collide more often and produce more effective collisions

The following energy graphs are for 5 different reactions at equilibrium. Which reaction is a fast exothermic reaction?

B

A flask contains two compartments (A and B) with equal volumes of solution separated by an osmotic membrane. Which diagram represents the final level of the liquids if "A" is initially a 10% glucose solution and "B" is initially a 20% glucose solution?

B will be higher than A

The following energy graphs are for 5 different reactions at equilibrium. Which reaction is a slow endothermic reaction?

C

Which letter represents the chemical energy of the products?

D

The following energy graphs are for 5 different reactions at equilibrium. Which reaction has almost the same amount of reactants as products at equilibrium?

D or E

which letter represents the chemical energy of the reactants

E

What type of reaction is metabolizing a cupcake? (endo or exo)

Exothermic

Why does the rate of a chemical reaction increase with increase concentration of one or more of the reactants?

Increase concentration of the reactant will increase the frequency of effective collisions

Ringer's solution is used to treat burns. It is prepared by dissolving 8.6 grams of NaCl, 0.30 g of KCl and 0.33 grams of CaCl2 in water and diluting to a volume of 1.0 liters. Which of the following statements are true concerning Ringer's solution? (give all answers)

Ringer's solution is an aqueous solution, Ringer's solution is homogenous

An unknown volume of water is added to 75 mL of a 3.5M solution of sodium chloride. What can be said of the resulting solution?

The concentration of the new solution will be less than 3.5M

Which statement concerning a reversible reaction at equilibrium is FALSE?

The concentration of the products is equal to the concentration of reactants

What is the energy of activation for a reaction?

The energy barrier the reactants must overcome in order to form the products

A student mixes 4 grams of KNO3 with 50 mL of water at room temperature and observes that most, but not all of the KNO3 has dissolved. Which statement concerning this solution is true?

The solution that is formed is a saturated solution

what can alter the activation energy of a reaction

adding a catalyst

What type of change is melting an ice cube? (endo or exo)

endothermic

What type of reaction is electrolysis of water (H2O to H2 and O2)? (endo or exo)

endothermic

What type of reaction is it where the products have more chemical energy than the reactants? (endo or exo)

endothermic

What type of reaction is photosynthesis? (endo or exo)

endothermic

What type of reaction represented by the following graph? (endo or exo)

endothermic

What type of change is it when it snows? (endo or exo)

exothermic

What type of reaction has a delta H? (endo or exo)

exothermic

What type of reaction is burning gasoline? (endo or exo)

exothermic

A person with a fever will have a slower respiration rate than before getting sick (true or false)

false

A reaction with a high energy of activation will be a very fast reaction (true or false)

false

A reaction with a high energy of activation will be a very fast reaction (true or false) duplicate

false

A solid block of iron will react faster than iron filings (true or false)

false

At 20 C, the solubility of KBr is 60 grams/100 grams of water. Increasing the pressure above the solution will likely increase the solubility of KBr (true or false)

false

Dialysis membranes have smaller pores than osmotic membranes (true or false)

false

Endothermic reactions can be favorable (true or false)

false

Exothermic reactions are always spontaneous (true or false)

false

Osmosis is the movement of solvent through a semipermeable membrane from a higher concentration of solute to lower concentration (true or false)

false

Since living cells are surrounded by biological solutions separated by semipermeable membranes, the osmotic pressure in the cell must be higher that the solution outside the cell (true or false)

false

The greater the osmols of a solution, the higher the vapor pressure (true or false)

false

a polar and non-polar liquid will be miscible (true or false)

false

all favorable reactions are spontaneous (true or false)

false

all ionic solids are soluble in water (true or false)

false

only solids dissolve in water to form solutions (true or false)

false

when the position of the equilibrium for a reaction "lies to the left", it means that at equilibrium the concentration of reactants is less than that of products (true or false)

false

A red blood cell is placed in a solution and the cell begins to swell. How is the solution classified (as compared to the cell)?

hypotonic

What term is used to describe a solution of lower osmolarity compared to one with a higher osmolarity?

hypotonic

In the reaction 2 C2H6 + 7O2 = 4CO2 + 6H2O, (not an equilibrium reaction), increasing the concentration of C2H6 will have what effect on the reaction?

increase the reaction rate

A flask contains a 2M solution of KCl. If more water is added to the flask, what will happen to the molarity?

less than 2M

A flask contains a 2M solution of KCl. If more water is added to the flask, what happens to the moles of KCl?

moles stay the same

What happens if more solvent is added to a saturated solution in equilibrium with undissolved solute?

more solute dissolves

What is the boiling point of a salt solution? (Assume sea level and normal atmospheric pressure) -less than 100 C -more than 100 C -exactly 100 C

more than 100 C

What happens if more solute is added to a saturated solution in equilibrium with undissolved solute?

nothing happens to the concentration of the solution (but there is more undissolved solute at the bottom)

What term describes a solution that is in equilibrium with undissolved solute?

saturated

What type of membrane allows only solvent molecules to pass through but not any solute molecules?

semipermeable osmotic membranes

Which is true of a dialysis membrane? (give all answers) - Only water can move through - large molecules like proteins can move through - small molecules like glucose and urea can move through - the kidneys are dialysis membranes

small molecules like glucose and urea can move through, the kidneys are dialysis membranes

What needs to happen for a reversible reaction to reach equilibrium?

the rater of the forward reaction equals the rate of the reverse reaction

The formation of rust (Fe2O3) on an exposed piece of iron typically takes several months. The reaction is: 4Fe(s) + 3O2(g)= 2Fe2O3(s) [Not a reversible reaction] what is true

the reaction has a very slow reaction rate, the reaction would be faster in summer than winter (assuming summer has higher temperatures than winter), Adding MnO2 (a catalyst) would make the reaction faster

Which letter represents the heat given off in the reaction?

there is no heat given off in this reaction

A collision between reactant molecules that produce a product (or products) is called an effective collision (true or false)

true

All spontaneous reaction must be exothermic (true or false)

true

As the temperature goes up, molecules will collide more often (true or false)

true

As the temperature goes up, more molecules will have enough energy to react (true or false)

true

At 20 C, the solubility of KBr is 60 grams/100 grams of water. Increasing the temperature of the solution will likely increase the solubility of KBr (true or false)

true

By adding salt to ice, the ice will melt at temperature below 0 C (true or false)

true

Enzymes are proteins that act as biological catalysts (true or false)

true

For most ionic solids, solubility in water generally increases as temperature increases (true or false)

true

Polar molecular solids (like glucose) are soluble in water because water is so polar (true or false)

true

The presence of a nonvolatile solute will reduce the vapor pressure of the solvent above the solution (true or false)

true

The presence of a solute reduces the vapor pressure of the solvent above the solution, raising its boiling point (true or false)

true

The speed of a reaction will depend on the energy of activation and not how exothermic it is (true or false)

true

Two solutions with the same osmotic pressure are said to be isotonic (true or false)

true

catalysts lower the energy of activation, making the reaction faster (true or false)

true

colligative properties depend on the concentration of particles in solution rather than their identity (true or false)

true

Container "A" has a 2% NaCl salt solution and container "B" has a 10% NaCl salt solution. The two containers are separated by a semipermeable osmotic membrane. What will happen?

water flows from A to B and the salt does not move

What happens when a red blood cell is placed in a solution which is hypertonic to the cell?

water will move out of the RBC, and the cell will burst