Sunday
July 5, 2015

Posts by Cortney


Total # Posts: 89

chemistry
how to make a buffer with 25 drops of 1.0 M acetic acid and 10 to 25 drops of sodium acetate
May 9, 2015

Chemistry
A chemist needs to prepare a buffer solution of pH 8.80. What molarity of NH3 (pKb = 4.75) is required to produce the buffer solution if the (NH4)2SO4 in the solution is 1.8 M?
May 6, 2015

chemistry
Suppose you add 2.0 mL of 0.10 M HCl to 100 ml of buffer having 0.10 M HA and 0.20 M NaA. a. Which species will react strongly with one another? I believe the answer is Cl- and Na+ to form NaCl. b. What will be the change in pH? pKa = 4.82 I am not sure how to find the answer ...
May 6, 2015

Chemistry
A solution is prepared by titrating a 100.0 mL sample of 0.10 M HF (Ka = 7.2 × 10-4) with 0.10 M NaOH.What is the pH after 20.0 mL of the 0.10 M NaOH is added?
May 6, 2015

chemistry
why does the neutrality in the blood depends on the concentrations of [H+] and [OH-] rather than pH.
May 6, 2015

chemistry
Is C2O4H- more likely to act as an acid or base
April 24, 2015

chemistry
If you had left your copper(II) nitrate/potassium hydroxide precipitate stand for a while, the precipitate would turn into a black powder. The copper doesn’t reduce in this reaction, but one mole of water is produced from the reaction of one mole of the copper precipitate...
April 23, 2015

Chemistry
the answer was c in case you were wondering
April 19, 2015

Chemistry
Two atoms with charges of +1 and -1 are separated by a distance of 0.5 angstroms. What would happen to the lattice energy between ions if the distance increases to 2 angstroms? A. The lattice energy decreases by a factor of 4. B. The lattice energy increases by a factor of 16...
April 19, 2015

chemistry
Is the answer B then??
April 9, 2015

chemistry
For the weak hypochlorous acid (HClO), which statement is true at the point halfway to the equivalence point? A. The total amount of HClO is equal to the pKa. B. The total amount of HClO is equal to ClO-. C. The total amount of H3O+ is equal to the amount of OH- . D. The total...
April 9, 2015

ideas for research
Find an article in an online Spanish language newspaper that interests you. Find another article in an online newspaper near where you live on the same topic or event. Then write a three paragraph report comparing and contrasting the different viewpoints of the two cultures. ...
April 8, 2015

chemistry
I think the answer could be B because in order for a reaction to occur it must be a favored reaction
April 7, 2015

chemistry
What must be true for a substance to dissolve in water? A. The entropy term must be positive. B. The enthalpy and entropy terms must combine for a favored reaction. C. The free energy change of dissolving must be positive. D. The energy required to break bonds apart must be ...
April 7, 2015

Chemistry
I did exactly what you said to do and I got the answer wrong. I Got A but the answer was B. Please explain.
April 7, 2015

Chemistry
An aqueous solution of 0.25 M silver nitrate, AgNO3, and 0.25 M iron(II) nitrate, Fe(NO3)2, are allowed to come to equilibrium in the following chemical reaction:
Ag+(aq) + Fe2+(aq) Fe3 + (aq) + Ag(s)
If the equilibrium constant, Kc, for the reaction is 3.0 ×...
April 7, 2015

Chemistry
What intermolecular forces are responsible for neoprene's stretchiness?
March 29, 2015

chemistry
the answer was c
March 25, 2015

chemistry
A spark plug fires before the gases in a cylinder are fully compressed. How will the engine be affected? A. The engine will get better gas mileage as less fuel is burned during each cycle. B. There will be fewer pollutants as the fuel has more time to burn. C. The gases will ...
March 25, 2015

chemistry
If it takes 30 seconds for a reactant concentration to decrease from 1.0 M to 0.5 M in a first-order chemical reaction, then what is the rate constant for the reaction? A. 43 s–1 B. 0.046 s–1 C. 0.023 s–1 D. 0.033 s–1
March 25, 2015

chemistry
How can the overall order of a reaction be determined? A. Add the exponents in an equilibrium constant expression. B. Add the coefficients in the balanced equation. C. Count the number of different reactants. D. Examine experimental data for the reaction over time.
March 25, 2015

Chemistry
A student tested the effect of temperature on the decomposition of N2O5. He found that the rate of the reaction at a lower temperature was 4.2 x 10–3 s–1 and the rate at a higher temperature was 1.6 x 101 s–1. What is wrong with the student's data? A. ...
March 25, 2015

math
1. the answer is b. 2. -14 is correct
March 24, 2015

Math-I don't quite get it.
First make the bottom the same There is 25/30 yards. We need 1/5 of this which would be 5/30 or 1/6 yards. Does this make sense?
March 24, 2015

chemistry
A spark plug fires before the gases in a cylinder are fully compressed. How will the engine be affected? A. The engine will get better gas mileage as less fuel is burned during each cycle. B. There will be fewer pollutants as the fuel has more time to burn. C. The gases will ...
March 24, 2015

chemistry
Ok so with 1.2 mols of NaN3 you have 1.8 mols of nitrogen gas. How do I convert it to liters?
March 24, 2015

chemistry
What volume of nitrogen gas at STP can form from 1.20 mol NaN3? 2NaN3(s) 2Na(s) + 3N2(g) A. 40.3 L B. 1.20 L C. 13.4 L D. 1.80 L
March 24, 2015

Chemistry
The answer is c sorry
March 24, 2015

Chemistry
How many moles of gas will occupy 6.75 m^3 at 65.0°C and 3.28 x 10^5 Pa? A. 7.98 x 10^4 mol B. 4.10 x 10^3 mol C. 7.88 x 10^2 mol D. 4.15 x 10^5 mol
March 24, 2015

Chemistry
How many moles of gas will occupy 6.75 m3 at 65.0°C and 3.28 x 105 Pa? A. 7.98 x 104 mol B. 4.10 x 103 mol C. 7.88 x 102 mol D. 4.15 x 105 mol
March 24, 2015

chemistry
A spark plug fires before the gases in a cylinder are fully compressed. How will the engine be affected? A. The engine will get better gas mileage as less fuel is burned during each cycle. B. There will be fewer pollutants as the fuel has more time to burn. C. The gases will ...
March 24, 2015

chemistry
So would the answer be NH3 since its molar mass is 17 vs 32 (o2), 44 (CO2), and 70 (Cl2)
March 24, 2015

chemistry
The molecules of which gas have the greatest velocity at 120°C? A. O2 B. CO2 C. NH3 D. Cl2
March 24, 2015

chemistry
Which of the following is not a physical property of gases? A. Low density B. No thermal expansion C. No fixed shape D. Compressibility I believe the answer is B
March 24, 2015

chemistry
So is the answer A.
March 24, 2015

chemistry
What are the parameters of a sample of gas that are all interrelated and affect each other when any one of them changes? A. Pressure, volume, number of moles, and temperature B. Shape, hardness, transparency, and odor C. Mass, density, color, volume, and pressure D. ...
March 24, 2015

Chemistry
It turns out you were wrong; The true answer is B.
March 23, 2015

Chemistry
I am so confused. All the answers make no sense. I know the answer has to be A,B or D because of the volume but which one do I choose? A?
March 23, 2015

Chemistry
it goes in the same directions. If temperature increase then the other properties have to increase
March 23, 2015

Chemistry
after looking at graphs I know believe the answer is D. What do you think?
March 23, 2015

Chemistry
is the answer B?
March 23, 2015

Chemistry
Which properties of a gas increase linearly as the temperature is increased? A. Volume and density B. Volume and pressure C. Amount of gas and density D. Amount of gas and volume I believe the answer is A or D But I am pretty sure the answer is a
March 23, 2015

Chemistry
A spark plug fires before the gases in a cylinder are fully compressed. How will the engine be affected? A. The engine will get better gas mileage as less fuel is burned during each cycle. B. There will be fewer pollutants as the fuel has more time to burn. C. The gases will ...
March 23, 2015

chemistry
never mind the answer is D
March 23, 2015

chemistry
During which stroke of a four-stroke internal combustion engine is work done to the system of gases? A. Exhaust stroke B. Intake stroke C. Compression stroke D. Power stroke
March 23, 2015

Chemistry
so the answer is C?
March 23, 2015

Chemistry
Gases can be differentiated from solids and liquids because gases have: A. reduced chemical reactivity. B. no color. C. average densities on the order of 10-3 g/mL. D. a spherical shape. I think the answer is C or D.
March 23, 2015

chemistry
Which properties of a gas increase linearly as the temperature is increased? A. Volume and density B. Volume and pressure C. Amount of gas and density D. Amount of gas and volume I believe the answer is A or D But I am pretty sure the answer is a
March 23, 2015

Chemistry
Which of the following best applies to the pressure of a gas? A. It is the force per unit volume. B. It decreases with temperature. C. It increases with volume. D. It is the sum of the collisions of the molecules. Is it a or d.
March 23, 2015

Chemistry
After being heated, an enzyme loses its ability to catalyze a reaction. What change occurred to the enzyme? A. A physical change, because cooling will restore the enzyme's function C. A physical change, because intermolecular forces were overcome
March 19, 2015

Chemistry
Which argument supports the claim that dissolving solid calcium chloride (CaCl2) in water is a chemical change? A. The ionic bond between the calcium ions and chloride ions is broken. B. The solid calcium chloride can be recovered by evaporating the water. C. The ions present ...
March 19, 2015

chemistry
The correct answer was B. If you are not sure with your answers you shouldn't be helping
March 19, 2015

chemistry
I know its not c because the entropy has to increase
March 19, 2015

chemistry
As an ionic solid dissolves in water, the temperature of the solution increases. What best describes the enthalpy and entropy of the solution? A. The enthalpy change is negative, and the entropy decreases. B. The enthalpy change is negative, and the entropy increases. C. The ...
March 19, 2015

chemistry
the answer was a
March 19, 2015

chemistry
What is the strongest intermolecular force that occurs between methane (CH4) and ammonia (NH3)? A. Dipole-induced dipole attractions B. Hydrogen bond C. London dispersion forces D. Dipole-dipole forces Is that answer c?
March 19, 2015

Chemistry
Never mind. The answer was D.
March 19, 2015

Chemistry
sorry the question was Why is it possible to float a pin on the surface of water?
March 19, 2015

Chemistry
A. The molecules of water on the surface change bonding as they dry out. B. The density of the pin is less than that of the water's surface. C. The surface tension of the water is so low. D. The force exerted by the mass of the pin does not increase the surface area ...
March 19, 2015

chemistry
Why is it possible to float a pin on the surface of water? A. The molecules of water on the surface change bonding as they dry out. B. The density of the pin is less than that of the water's surface. C. The surface tension of the water is so low. D. The force exerted by ...
March 18, 2015

chemistry
As an ionic solid dissolves in water, the temperature of the solution increases. What best describes the enthalpy and entropy of the solution? A. The enthalpy change is negative, and the entropy decreases. B. The enthalpy change is negative, and the entropy increases. C. The ...
March 18, 2015

Chemistry
intermolecular forces; require less energy to break. Intermolecular forces are not called bonds precisely for this reason. There is a significant difference between the amount of energy between two bonded atoms and two atoms in separate molecules held together by ...
March 18, 2015

Chemistry
The answer was B
March 18, 2015

Chemistry
______________ are similar to covalent bonds in that they hold atoms together. They are different from covalent bonds in that they ___________ . A. Ionic bonds; hold atoms together within a molecule B. Intermolecular forces; require less energy to break C. Intermolecular ...
March 18, 2015

chemistry
How do intermolecular forces determine the vapor pressure of a liquid? A. A nonpolar compound has a low vapor pressure because of London dispersion forces. B. A compound that can form hydrogen bonds has a low vapor pressure. C. A polar compound has a high vapor pressure ...
March 18, 2015

Chemistry
Which of the following statements is (or are) true? I. All polar molecules have dipole moments. II. All polar molecules have oppositely charged regions. III. A polar molecule is attracted to other molecules because of electrostatic forces. IV. All polar molecules have hydrogen...
March 18, 2015

chemistry
1. What is the cause of a gas sample exerting pressure on its surroundings, such as a container? A. The sum of the volumes of all the gas particles in the sample B. Chemical reactions with the container walls C. Collisions of particles of gas D. The weight of the particles on ...
March 18, 2015

chemistry
1. Ideal gas particles: A. have no mutual attraction and no individual volume. B. have no mass or volume. C. have no odor and no color. D. have no density and do not form bonds. Is it A? 2. Why does the density of gas in a hot air balloon decrease as the gas is heated? A. The ...
March 18, 2015

Chemistry
How does table salt (NaCl) dissolve in water? A. The oxygen atoms in water molecules attract sodium ions. B. Each sodium ion is surrounded by chloride ions. C. Each NaCl molecule is surrounded by water molecules. D. Water molecules hydrogen bond with sodium ions and chloride ...
March 18, 2015

chemistry
To dissolve an ionic solid in water, you must first disrupt the ionic bonds that are holding the ionic lattice together. This is an endothermic process, yet many ionic solids have an exothermic heat of solution. (Heat is released when the ionic solid is dissolved.) This is ...
March 17, 2015

Chemistry
Liquid methyl alcohol, which has polar molecules, will dissolve: A. only solutes that are other polar liquids. B. only solutes that are other liquids. C. nonpolar solutes. D. polar solutes. Is the answer d.
March 17, 2015

chemistry
Which step during the dissolving process releases energy? A. Separating solute particles from one another B. Adding solute into the solvent C. Separating solvent particles from one another D. Mixing the particles of solute with particles of solvent
March 17, 2015

Chemistry
so the answer is c
March 17, 2015

Chemistry
Olive oil has a higher viscosity than benzene. Which statement best explains the reason for the difference in viscosity between these two liquids? A. Molecules of olive oil take up a smaller volume than molecules of benzene. B. Fewer intermolecular forces exist between ...
March 17, 2015

Chemistry
I just want to make sure that D is the correct answer. Each halogen is a diatomic element. However, under normal conditions chlorine is a gas, bromine is a liquid, and iodine is a solid. What is the best explanation for this difference? A. The strength of the covalent bond ...
March 17, 2015

chemistry
I believe the answer is c I just wanted to make sure. What can help overcome a positive enthalpy of solution and allow a solid solute to dissolve in water? A. A decrease in entropy B. A large amount of energy released C. An increase in entropy D. A large amount of energy absorbed
March 17, 2015

grammer
How about this? Even in Hollywood, the practice of blacklisting became know. Entertainment figures were denied jobs because they were suspect for supporting communism.
March 17, 2015

Chemistry
lead
April 28, 2012

chemistry
Determine the mass of Co(NO3)2•6 H2O to prepare 250 mL of a 0.50 M stock solution.
March 28, 2012

Math
In a math class there are 28 students. Each student has a 90% chance of attending any given class and students act independently. What is the probability that tomorrow's class has perfect attendance?
March 22, 2012

grammar
YES!
October 20, 2011

Functions
write a function. f(x), that represents the cost of renting a car for x days with a total of 80 kilometers if there is a fixed charge of $17 per day and a charge of $0.35 per kilometer.
October 20, 2011

Functions
Janice is running a 7613 meter race. Assume the she runs at a constant speed of 287 meters per minute. Express the function f(t) that gives her distance from the finishing line t minutes after the start of the race.
October 20, 2011

Math
Janice is running a 7613 meter race. Assume the she runs at a constant speed of 287 meters per minute. Express the function f(t) that gives her distance from the finishing line t minutes after the start of the race.
October 20, 2011

Math
write a function. f(x), that represents the cost of renting a car for x days with a total of 80 kilometers if there is a fixed charge of $17 per day and a charge of $0.35 per kilometer.
October 20, 2011

pre-algebra
measuring your heart rate is one way to check the intensity of exercise. studies show that a person's maximum heart rate depends on his or her age. The expression 220-a approximates a person's maximum heart rate in beats per minute, where a is the person's age.find...
August 15, 2011

3rd grade
show me a base-ten drawing
November 29, 2010

10th grade English
wat a noun
February 23, 2009

Japanese
I need someone to correct my translations... Can you please help :(... at least some, here they are: 1.
January 9, 2007

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