Thursday

January 29, 2015

January 29, 2015

Total # Posts: 22

**Chemistry (PLS HELP ASAP)**

OK... so I found the temp to be 298, and the moles (n) = .0089921441, but now you are saying to find the molecular mass...what is RMM? and where do I go from here?
*January 11, 2010*

**Chemistry (PLS HELP ASAP)**

What is the molecular weight of a gas if a 15.0g sample has a pressure of 836 mm Hg at 25.0 degrees C in a 2.00 L flask? a)167 b)1.35 c)176 d)11.1 e)none of the above Please explain... I need to understand how to do this. Thanks. I know that I have to use PV=nRT, then solve ...
*January 11, 2010*

**Chemistry**

What type of reaction occurs when potassiumbromide solution is mixed. With lead(II) acetate solution? Gas evolution, oxidation reduction, precipitation, acid-base neutralization, or no reaction
*January 8, 2010*

**Chemistry**

A 0.125-g sample of monoprotic acid of unknown molar mass is dissolved in water and titrated with 0.1003 M NaOH. The endpoint is reached after adding 20.77 mL of base. What is the molar mass of the unknown acid?
*January 4, 2010*

**Chemistry**

I'm sorry... I accidently reposted this--it is not answered yet though.
*January 4, 2010*

**Chemistry**

A 25.00-mL sample of an H2SO4 (2 and 4 are subscripted) solution of unknown concentration is titrated with a .1328 M KOH solution. A volume of 38.33 mL of KOH was required to reach the endpoint. What is the concentration of the unknown H2SO4 (again, the 2 and 4 are subscripted...
*January 4, 2010*

**Chemistry**

A 25.00-mL sample of an H2SO4 (2 and 4 are subscripted) solution of unknown concentration is titrated with a .1328 M KOH solution. A volume of 38.33 mL of KOH was required to reach the endpoint. What is the concentration of the unknown H2SO4 (again, the 2 and 4 are subscripted...
*January 4, 2010*

**Chemistry**

A sample of helium gas initially at 37.0 degrees C, 785 torr and 2.00 L was heated to 58.0 degrees C while the volume expanded to 3.24 L. What is the final pressure in atm? a)1.79 b)3.21 c)0.681 d).517 e)none of the above please explain--I need to know how to do this--this is ...
*January 3, 2010*

**chemistry**

what is the initial temperature (in degrees C) of a system that has the pressure decreased by 10 times while the volume increased by 5 times with a final temperature of 150 K? a)27 b)75 c)300 d)-198 e) none of the above Please explain--I need to know how to do this--this is ...
*January 3, 2010*

**Chemistry**

What is the molecular weight of a gas if a 15.0g sample has a pressure of 836 mm Hg at 25.0 degrees C in a 2.00 L flask? a)167 b)1.35 c)176 d)11.1 e)none of the above Please explain... I need to understand how to do this. Thanks.
*January 3, 2010*

**chemistry**

In a lab, .0092 moles of Cu were reacted with .0046 miles of S. What would happen to the mole Cu/mole S ratio if some of the copper was unreacted (increase, decrease, stay the same)? Also, what will happen to the mole Cu/ Mole S ratio if unreacted sulfur remains in the ...
*January 1, 2010*

**Math**

A photo width is 2 in. more than it's length. A borderof 1 in is placed around the photo, and the area covered by the photo and it's border is 120 sq. inches. Find the dimensions of the photo itself.
*December 14, 2009*

**math**

Use properties of logarithms to condense the logarithmic expression. Write the expression as a single logarithm whose coefficient is 1. Where possible, evaluate logarithmic expressions. 8 ln x -(1/3) ln y Choose one answer. a. ln x^8 y^3 b. ln x^8 /3"sqrt"y c. ln x^8...
*December 6, 2009*

**Math**

Solve the equation. (the 6s are supposed to be sub-scripted, but I can't type subscripts) Problem: log6 7 - log6 x = 4 Choose one answer. a. 7/24 b. 7/1296 c. 7/4 d. 1296/7 I am so lost, can you please help me understand this? I need to know how to do this, so please don&#...
*December 6, 2009*

**Chemistry**

What is the final concentration (M) of a solution prepared by diluting 50.0 mL of a 6.00 M KCl solution to a volume of 0.500 L? A. 1.67 B. 0.600 C. 0.0167 D. 3.0 E. none of these My initial thought was to take the 6.00 M KCl/0.500 L, for an answer of 12. This baffles me that ...
*November 21, 2009*

**Chemistry**

Dr Bob, First let me thank you for your help and explanations, so that I can understand what I'm supposed to be doing--it's much appreciated! I have a question though, at what point do I know that a solution would be saturated, supersaturated, unsaturated, etc. I know ...
*November 21, 2009*

**Chemistry**

Given that the solubility of sodium chloride is 36 grams per 100 grams of water. Which of the following solutions would be considered supersaturated? A. dissolve 5.8 moles of NaCl in 1 L of water B. dissolve 1.85 moles of NaCl in 300 ml of water C. dissolve 3.25 moles of NaCl ...
*November 21, 2009*

**Dr. Bob...Chemistry**

you just answered a question for me, but the following are my answers to choose from. it was the 2nd question that I posted. about hydrocloric acid solution mixing with sodium bicarbonate. So, my answers to choose from are gas evolution, precipitation, acid-base neutralization...
*November 20, 2009*

**Chemistry**

so, my answers to choose from are gas evolution, precipitation, acid-base neutralization, and oxidation... I'm confused
*November 20, 2009*

**Chemistry**

what type of reaction occures when a hydrochloric acid solution is mixed with a sodium bicarbonate solution? I chose gas evolution, but am wondering if it is acid-base neutralization instead.
*November 20, 2009*

**Chemistry**

ty Dr. Bob...
*November 20, 2009*

**Chemistry**

What gas is produced when hydrochloric acid is reacted with ammonium carbonate?
*November 20, 2009*

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