# Posts by nevaeh

Total # Posts: 78

**Chemistry**

Which is the electrophilic site in the molecule (CH3)2C=O? A. CH3 carbon B. CH3 hydrogen C. C=O carbon D. C=O oxygen I think the answer is D. because oxygen is electronegative and wants to hog electrons this making it electrophilic. Is this correct?

**Organic Chemistry**

How many constitutional isomers have the molecular formula C3H6S ?

**Chemistry**

Rank the following atoms in order of decreasing electronegativity, putting the most electronegative first: F, Ne, O, N, C

**English-Grammar**

Is the following correct? "The abysmal absence of food deprived me of energy."

**Chemistry/- Dr.Bob222**

A voltaic cell consists of a Zn/Zn2+ half-cell and a Ni/Ni2+ half-cell at 25 C. The initial concentrations of Ni2+ and Zn2+ are 1.50 M and 0.10 M, respectively. a. What is the initial cell potential? My answer: 0.56 B b. What is the cell potential when the concentration of Ni2...

**Chemistry - Dr.Bob**

Predict the half-reactions occurring at the anode and the cathode for the electrolysis of aqueous Na2SO4.

**Chemisty-Dr.Bob222**

Determine the minimum concentration of the precipitating agent on the right to cause precipitation of the cation from the solutions to the left. a. 0.035 M BaNO3; NaF b. 0.085 M CaI2 ; K2SO4 c. 0.0018 M AgNO3 ; RbCl My work: Are my answers correct? a. BaNO3 + NaF --> BaF2...

**Chemistry- Dr.Bob222**

What is the solubility of AgCl in 10 M NH3? The Kf of Ag(NH3)2+ from AgCl(s) in aqueous NH3 is 0.0031, which is for the balanced reaction shown below. AgCl(s) + 2 NH3(aq) → Ag(NH3)2+(aq) + Cl-(aq) Work: Ksp = x^2 /(2x+10)^2 = 1.8 x 10^-10 Now I am confused....... At ...

**Chemistry- Dr.Bob222**

I do not quiet understand what you said. Could you show your work. What is the solubility of AgCl in 10 M NH3? The Kf of Ag(NH3)2+ from AgCl(s) in aqueous NH3 is 0.0031, which is for the balanced reaction shown below. AgCl(s) + 2 NH3(aq) → Ag(NH3)2+(aq) + Cl-(aq)

**Chemistry- Dr.Bob222**

Question 2 What is the solubility of AgCl in 10 M NH3? The Kf of Ag(NH3)2+ from AgCl(s) in aqueous NH3 is 0.0031, which is for the balanced reaction shown below. AgCl(s) + 2 NH3(aq) → Ag(NH3)2+(aq) + Cl-(aq) Is the answer 0.557 M?

**Chemistry**

I got pH = 5.3 A 1.00 L buffer solution is 0.250 M in HC2H3O2 and 0.250 M in NaC2H3O2. Calculate the pH of the solution after the addition of 0.150 mol of solid NaOH. Assume no volume change upon the Additon o f NaOH. The Ka value for HC2H3O2 at 25 C is 1.8 x 10^-5. Chemistry-...

**Chemistry-Dr.Bob222**

A 1.00 L buffer solution is 0.250 M in HC2H3O2 and 0.250 M in NaC2H3O2. Calculate the pH of the solution after the addition of 0.150 mol of solid NaOH. Assume no volume change upon the Additon o f NaOH. The Ka value for HC2H3O2 at 25 C is 1.8 x 10^-5.

**Chemistry-Dr.Bob222**

Calculate the molar solubility of calcium hydroxide in a solution buffered at each pH. a. pH=4 b. pH= 7 c. pH=9

**Chemistry-Dr.Bob222**

Consider the compounds with the generic formula listed and their corresponding molar solubilities in pure water. Which compound has the smallest value of Ksp? a. AC; molar solubility = 1.35 x 10^-4 M b. AX2; molar solubility = 2.25 x 10^-4 M c. A2X; molar solubility= 1.75 x 10...

**Chemistry- Dr.Bob222**

Is there an actual value for the buffer capacity of acetic acid? I need to know the actual value, so that I can calculate the percent error for my lab.

**Chemistry**

A 500 mL buffer solution is 0.1 M benzoic acid and 0.10 M in sodium benzoate and has an initial pH of 4.19. What is the pH of the buffer upon addition of 0.010 mol of NaOH?

**Chemistry -Dr.Bob222**

Arrange the solutions in order of increasing acidity. NaCl, NH4Cl, NaHCO3, NH4CLO2, NaOH

**Grammar**

Which is correct? The usefulness of learning is considered valuable. OR The learning usefulness is considered valuable.

**Chemistry**

Like a equilibrium constants, the values of Kw depends on temperature. At body temperature (37 C), Kw= 2.4 x 10^-14. What are the [H3O+] and pH of pure water at body temperature?

**math**

Jay purchased a new leather jacket on sale at a 40% discount. The origanal list price was $320. What wad the amount of the discount. I just need to learn how to do this kind of question because my teacher did not teach me this.

**Chemistry- Dr.Bob222**

Determine [H30+], [OH-], and pH. A solution that is 0.655% HNO3 by mass (assume a density of 1.01 g/ mL for the solution).

**Chemistry-Dr.Bob222**

Like a equilibrium constants, the values of Kw depends on temperature. At body temperature (37 C), Kw= 2.4 x 10^-14. What are the [H3O+] and pH of pure water at body temperature?

**Chemistry-Dr.Bob222**

A 25.0 mL sample of 0.125 M pyridine is titrated with 0.100 M HCl. Calculate the pH at 0 mL of added acid.

**Dr.Bob**

A 100.0 mL sample of 0.05 M NH3 is titrated with 0.10 M HCl. Determine the pH of the solution after the addition of 50.0 mL HCl. Here is my work: NH3 + H3O+ --> NH4+ + H2O Before Addition: NH3= 0.005 mol H3O= 0 mol NH4+ = 0 mol Addition: NH3 = 0.005 mol H3O+ = 0.005 mol NH4...

**Chemistry- Dr.Bob**

A 40.0 mL sample of 0.100 M HNO2 is titrated with 0.200 M KOH. Calculate the pH at the equivalence point for the titration of HNO2 and KOH. When I did this problem again, I got pH= 8.08. Is this close to your answer? Dr.Bob: I estimated the pH and didn't come close to 11 ...

**Chemistry-- Dr Bob, here is my work**

Actually, when I did the problem again, I got 8.08. Is this correct?

**Chemistry**

A 40.0 mL sample of 0.100 M HNO2 is titrated with 0.200 M KOH. Calculate the pH at the equivalence point for the titration of HNO2 and KOH. I got pH= 11.74.

**Chemistry**

When titrating 50.0 mL of 0.10 M H2SO4 with 0.10 M NaOH, how many mL of NaOH will you have added to reach the 1st equivalence point? I am confused... What H2A problem? Chemistry-Dr.Bob222 - DrBob222, Tuesday, April 12, 2016 at 1:49am Refer to the H2A problem above BUT you only...

**Chemistry**

A student completes a titration of an unknown diprotic acid. In this experiment, 0.79 g of the acid is dissolved in 250.0 mL of water. It requires 13.48 mL of 1.0 M NaOH to reach the second equivalence point. What is the molar mass of the acid?

**Chemistry-Dr.Bob222**

A student completes a titration of an unknown diprotic acid. In this experiment, 0.79 g of the acid is dissolved in 250.0 mL of water. It requires 13.48 mL of 1.0 M NaOH to reach the second equivalence point. What is the molar mass of the acid?

**Chemistry-Dr.Bob222**

When titrating 50.0 mL of 0.10 M H2SO4 with 0.10 M NaOH, how many mL of NaOH will you have added to reach the 1st equivalence point?

**Geometry**

The outside diameter of a pipe is 5 cm. The inside diameter is 4 cm. The pipe is 4 meters long. What is the volume of the material used for this length of pipe?Round your answer to the nearest cubic centimeter. (Hint: be sure that all units are in centimeters when completing ...

**Chemistry- Dr.Bob222**

What is the pH of a solution that is 0.150 M in acetic solution and 0.300 M in sodium acetate? The Ka of acetic acid is 1.8 x 10^-5. My work: pH= pKa + log (base/acid) pH= -log (1.8 x 10^-5) + log (0.300/0.150) pH=5

**Chemistry-Dr.Bob222**

Determine [OH-] of a solution that is 0.135 M in CO3^2-. I got 0.00532.

**Chemistry- Dr.Bob222**

Ammonium hydroxide is commonly advertised as an ingredient in some window cleaners. Rank the following in order of decreasing concentrations in these solutions: NH4OH, NH4+, OH-, NH3. Explain your reasoning. (Note that kb for ammonia = 1.8 x 10^-5. So does an unionized ion ...

**Chemistry - Dr.Bob 222**

The pH scale ranges from 0 to 14. What is the range of the hydronium ion concentration covered by this scale?

**Art**

what is the answer

**Chemistry- Dr.Bob222**

Which if the folowin species is not amphoteric? a) H2SO4 b) H2PO4- c) HPO4 2- d) HSO4- e) H2O

**Math**

9+4=13 13/2=6.5 So the answer is 6.5

**Chemistry-DrBob222**

I got an answer of -1.34 x 10^3 KJ/mol. A 10.00 mL aliquot of 0.100 M NaOH is added to 15.00 mL of 0.100M HCl in a coffee cup calorimeter. The initial temperature of the two dilute liquids were both 25.0 degrees C and the final temperature of the mixture was found to be 37.8 ...

**Chemistry-DrBob222**

Is the answer for part c 0.91? A 1.0 L ball containing Ar at 5 atm is connected to a 10.0 L ball containing N2 at 2atm. A)Calculate the partial pressures and mole fractions of Ar and N2 after the valve is opened and the gases are allowed to mix (they fill the balls on both ...

**Chemistry-DrBob222**

Where did you get 5E-5. Is this how you set it up? 0.01 x 0.05 = 5E-4 If so, is it supposed to be 5E-4 instead of 5E-5? What is the equilibrium constant for a weak acid HA that dissociates 1% at an initial concentration of 0.05 M according to the following balanced chemical ...

**Chemistry- DrBob222**

What is the equilibrium constant for a weak acid HA that dissociates 1% at an initial concentration of 0.05 M according to the following balanced chemical equation? HA <----> H+ + A-

**Chemistry**

A 10.00 mL aliquot of 0.100 M NaOH is added to 15.00 mL of 0.100M HCl in a coffee cup calorimeter. The initial temperature of the two dilute liquids were both 25.0 degrees C and the final temperature of the mixture was found to be 37.8 degrees C. What is the (molar) heat of ...

**Chemistry-DrBob222**

I got 62.9 mL. Is this correct? I think HCl is the LR. A piece of solid magnesium is reacted with hydrochloric acid to form hydrogen gas: Mg (s) + 2HCl (aq) ---> MgCl2 (aq) + H2 (g) What volume of hydrogen gas (in mL) is collected over water at 25 degrees Celsius by ...

**Chemistry -DrBob222**

How many gallons of ethylene glycol, molar mass 62.07 g/mol, density = 1.1 g/mol do you need to add to each gallon of water ( 1 gallon = 4 liters and kf = 1.85 C/m) in your radiator to get the water to freeze at -15 C? Is it 0.458 gallon?

**Chemistry-DrBob222**

What is the final temperature and physical state if water when 47.50 kJ of energy is added to 15.0 g of ice at -10.0 C? Helpful information: Cs (ice) = 2.1 J/g C Heat of fusion (water) = 6.02 kJ/mol Cs (water) = 4.184 J/g C Heat of vaporization (water) = 40.7 kJ/mol Cs (steam...

**Chemistry**

A 1.0 L ball containing Ar at 5 atm is connected to a 10.0 L ball containing N2 at 2atm. A)Calculate the partial pressures and mole fractions of Ar and N2 after the valve is opened and the gases are allowed to mix (they fill the balls on both sides). My answers: P argon = 0....

**Chemistry-DrBob222**

A 1.0 L ball containing Ar at 5 atm is connected to a 10.0 L ball containing N2 at 2atm. A)Calculate the partial pressures and mole fractions of Ar and N2 after the valve is opened and the gases are allowed to mix (they fill the balls on both sides). My answers: P argon = 0....

**Chemistry- Dr.Bob222**

Predict the effect of decreasing the temperature on the position of the following equilibria. (a) H2(g) + Cl2(g) ↔ 2HCl(g) + 49.7 kJ My answer: shifts to the right (b) 2NH3(g) ↔ N2(g) + 3H2(g) ∆ H = 37.2 kJ My answer: shifts to the left (c) CO(g) + H2O(g) &#...

**chem**

never mind.. I got 0.10..

**chem- to DrBob222**

I got 0.08, but the answer is wrong!

**chem**

Exercise 14.55 Consider the reaction: NiO(s)+CO(g)⇌Ni(s)+CO2(g) Kc=4000.0 at 1500 K When calculating the answer, do not round to the appropriate number of significant figures until the last calculation step. If a mixture of solid nickel(II) oxide and 0.10000 M carbon ...

**Chemistry**

Exercise 14.55 Consider the reaction: NiO(s)+CO(g)⇌Ni(s)+CO2(g) Kc=4000.0 at 1500 K When calculating the answer, do not round to the appropriate number of significant figures until the last calculation step. If a mixture of solid nickel(II) oxide and 0.10000 M carbon ...

**Chemistry**

Exercise 14.55 Consider the reaction: NiO(s)+CO(g)⇌Ni(s)+CO2(g) Kc=4000.0 at 1500 K When calculating the answer, do not round to the appropriate number of significant figures until the last calculation step..

**Science/Math**

Give an analogy to illistrate how air pressure works

**7th grade English**

ugghh

**math**

COULD 35 ever be the product of 10 and another number?Explain

**counting cents**

Dara has 5 coins in her purse. The coins total 40 cents

**math**

541,641,741.what is the next number.

**time**

when the hour hand is pointing at ten and the minute hand is pointing at the five. what time is it

**math**

Draw a cookie that is divided into 2 equal parts.Write the fraction to go with your drawing.

**Math**

The answer is more than and 275 more because if u divide 13,750 by 50 you will get 275and if you divide 13,750 by 25 you will get 550 and is more than 275 Your welcome and sorry im so late but at least you know the answer now

**math**

an eight sided number cube has the numbers 1,2,3,4,5,6,7 and 8 on it. the number cube is thrown once. What is the probability of 2?

**math**

3,375

**Science**

ii am michelle

**Science**

shut the hell up nicole

**Math**

655

**Math**

Evan told his class that the people in his family have 14 legs in all. Quinton said that there must be 7 people in Evan's family. Is Quinton correct?Explain.

**english/check**

"About Russell" 28. Russell’s family encourages him to seek help for his problems. true false 29. Russell ends up a)working with his father as a real estate agent. b)collecting and redeeming soda bottles. c)begging on the street. d)teaching math in high school. ...

**Social Studies**

correct!

**math**

If there is an square 8 by 8, how many 4 sq ft tiles would i need?

**MATH**

$41

**Chemistry**

It's still not giving me the right answer. I'm pulling in the numbers, and doing the equation right. But, it keeps telling me, I am wrong.

**Chemistry**

(30.5)(X)(10.8)+(?)(10.8)=0 What number goes in the calorimeter constant ?

**Chemistry**

A 30.5 g sample of an alloy at 94.0°C is placed into 48.7 g water at 20.3°C in an insulated coffee cup. The heat capacity of the coffee cup (without the water) is 9.2 J/K. If the final temperature of the system is 31.1°C, what is the specific heat capacity of the ...

**Chemistry**

What is the change in internal energy (in J) of a system that absorbs 0.677 kJ of heat from its surroundings and has 0.438 kcal of work done on it?

**College Chemistry**

1. What is the change in internal energy (in J) of a system that absorbs 0.677 kJ of heat from its surroundings and has 0.438 kcal of work done on it? 2. A 30.5 g sample of an alloy at 94.0°C is placed into 48.7 g water at 20.3°C in an insulated coffee cup. The heat ...

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