Friday

July 25, 2014

July 25, 2014

Total # Posts: 290

**corrected repost chemistry**

to what volume should you dilute 125mL of an 8.00M CuCl2 solution so that 50.0mL of the diluted solution contains 5.9g CuCl2 I have a hard time determing the M1V1=M2V2 is

**chemistry**

Describe how you would make 500.0mL of a 0.200M NaOH solution from a 15.0 stock NaOH conentration

**chemistry**

a 3.5L sample of a 5.8M NaCl solution is diluted to 55L.What is the molarity of the diluted solution

**chemistry**

Hydrochloric acid is usually purchased in concentrated form with a 37.0% HCL concentration by mass and a density of 1.20g/mL. How much of the concentrated stock solution in milliliters should you use to make 2.5L of 0.500M HCL

**chemistry**

how much of a 1.50M solution sodium sulfate solution in milliliters is required to completely precipitate all the barium in 150.0mL of a 0.250 M barium nitrate solution

**chemistry**

A 45.8mL sample of 5.8M KNO3 solution is diluted to 1.00L. What volume of the diluted solution contains 15.0 g of KNO3.

**chemistry**

A KNO3 solution is made using 88.4g of KNO3 and diluting to a total soultion volume of 1.50l. Calculate the molarity and mass percent of the solution. Assume a density of 1.05 g/mL for the solution.

**chemistry**

an aqueous solution containing 17.5g of an unknown molecular(nonelectrolyte) compound in 100.0g of water has a freezing point of 1.8 degress C. calculate the molar mass of the unknown compound

**chemistry**

An ethylene glycol solution is mad using 58.5g of (C2H6O2) and diluting to a total volume of 500.0 mL. Calculate the freezing and boiling point. Assume a density of 1.09 g/ml for the solution

**chemistry**

A glucose solution contains 55.8g of glucose (C6H12O6) in 455g of water. Calculate the freezing poing and boiling point of the solution. (Assume a density of 1.00 g/ml for water. This what I did, I got moles of C6H12O6, 0.89 moles C6H12O6 then I got the mass of the solution 45...

**chemistry**

DrBob222 I think Im doing something wrong. When I worked this problem out I came up with the right answer but wrong units. 0.112L KOH x 0.100molKOH/LKOH x 1mol H3PO4/3 mol KOH x 0.01 L H3PO4/1 mol H3PO4 = 0.373 L H3PO4

**chemistry**

a 10.0mL sample of an unknown H3PO4 solution requirs 112mL of 0.100 M KOH to completely react with the H3PO4. What was the concentrartion of the unknown H3PO4 solution? H3PO4 + 3KOH -----> 3H2O + K3PO4 Ive seen these problems with one volume but not two volumes Im lost plea...

**chemistry**

where did you get the 96.2

**chemistry**

If im given mass percent and mass solvent how do I find mass solute and mass solution. example: Mass percent = 3.8% and Mass solvent 45.8 g. Find mass solute and mass solution

**Statistics**

The distribution of heights of adult males has a mean of 69 inches and a standard deviation of 4 inches. A random sample of 36 adult males is selected. Find the probability that the average height will be more than 70 inches. a.0.668 b.0.858 c.0.908 d.0.995

**statistics**

Suppose a random sample of 25 students is selected from a community college where the scores in the final exam (out of 125 points) are normally distributed, with mean equal to 112 and standard deviation equal to 12. Find the probability that the sample mean deviates from the p...

**chemistry**

an 8.5g ice cube is placed into 255g of water. Calculate the temp change in the water upon the complete melting of the ice. Hint: Determine how much heat is absorbed by the melting ice and then use q = mc^T to calculate the temp change of the 255g of water

**Chemistry**

A mixture containing 235 mg of Helium and 325 mg of neon has a total pressure of 453 torr. What is the partial pressure of Helium

**Chemistry**

Consider the chemical reaction C + H2O -----> CO + H2 How many liters of hydrogen gas are formed From the complete reaction of 1.07 mol of C? Assume that the hydrogen gas is collected at a pressure of 1.0 atm and the temperature of 315K So I'm looking for volume and I h...

**Chemistry**

Ahhhhh thank you!!!!! I was so frustrated

**Chemistry**

How many moles of gas must be forced into a 3.5 L ball to give it a gauge pressure of 9.4 psi at 25 degrees C? The gauge pressure is relative to atmospheric pressure. Assume that atmospheric pressure is 14.7 psi so that the total pressure in the ball is 24.1 psi Ok so I'm ...

**Chemistry**

In this reaction, 4.58 L of O2 were formed at 745mm Hg and 308 K. How many grams of Ag2O decomposed. 2 Ag2O----> 4 Ag + O2 Please help I'm very confused

**Chemistry**

A chemical reaction occurring in a cylinder equipped with a movable piston produces 0.58 mol of a gaseous product. If the cylinder contained 0.11 mol of gas before the reaction and had an initial volume of 2.1 L, what was it's volume after the reaction. Am I doing this rig...

**Chemistry**

A snorkeler takes a syringe filled with 16 mL of air from the surface, where the pressure is 1.0 ATM, to an unknown depth. The volume of the air in the syringe at this depth is 7.5 mL. What Is the pressure at this depth? If the pressure increases by an additional 1 atm for eve...

**Chemistry**

Convert a pressure of 23.8 in. Hg into kilopascal. Ok so I looked up kilopascal and it Said 1 Kpa = 1000 pa So I began to set it up like this 23.8 / 29.2 x1000 am I correct Chemistry - DrBob222, Thursday, October 13, 2011 at 1:48pm I don't think that will get it. I would ...

**Chemistry**

DrBob222 I used 29.2 in Hg because my book gave me 1 atm = 29.92 in. Hg. But why did you use 1atm/760mm

**Chemistry**

Convert a pressure of 23.8 in. Hg into kilopascal. Ok so I looked up kilopascal and it Said 1 Kpa = 1000 pa So I began to set it up like this 23.8 / 29.2 x1000 am I correct

**Chemistry**

Convert a pressure of 23.8 in. Hg into kilopascal. Ok so I looked up kilopascal and it Said 1 Kpa = 1000 pa So I began to set it up like this 23.8 / 29.2 x1000 am I correct

**chemistry**

How many moles of O2 are needed to form 3 moles of Al2O3 from the element

**Chemistry**

A thief uses a bag of sand to replace a gold statue that sits on a weight sensitive alarmed pedestal. The bag of sand and the statue have exactly the same volume 1.75 L. Assume that the mass of the bag is negligible. A) calculate the mass. ( density of gold = 19.3 g/cm3

**Stoichiometry**

I think I got it 6 mol A / 2 mol A x3 mol B = 9 mol B

**Stoichiometry**

So I have this question it reads Consider the generic chemical reaction How many moles of B are required to completely react with 2A + 3B ==> 3C 1. 6 mol of A 2. 2 mol of A I won't put them all just guide me in the right direction please

**Stoichiometry**

Consider the reaction between reactants S & O2 2S(s) + 3 O2(g) ==> 2 SO3(g) If a reactant vessel initially contains 5 mol S and 9 mol O2, how many moles of S, O2 and SO3 will be in the reaction vessel once the reactants have reached as much as possible? Assume 100% actual y...

**Stoichiometry**

Consider the reaction between reactants S & O2 2S(s) + 3 O2(g) ==> 2 SO3(g) If a reactant vessel initially contains 5 mol S and 9 mol O2, how many moles of S, O2 and SO3 will be in the reaction vessel once the reactants have reached as much as possible? Assume 100% actual y...

**Stoichiometry**

Find the limiting reactant for the initial quantities of reactants 2k(s) + Cl2(g)--> 2KCl(s) 1.8 mol K; 1 mol Cl2 I'm lost

**Stoichiometry**

Find the limiting reactant for the initial quantities of reactants 2k(s) + Cl2(g)--> 2KCl(s) 1.8 mol K; 1 mol Cl2 I'm lost

**Stoichiometry**

For each precipitation reaction, calculate how many grams of the first reactant are necessary to completely react with 17.3 g of the second reactant. 2KI(aq) + Pb(NO3)2(aq)--->PbI2(s) + 2KNO3(aq) Not looking for the answer I really want to know if I did it correctly 17.3g P...

**Chemistry **

Is it true that Na+ and K+ are always spectator ions in reactions that involve sodium and potassium compounds

**Chemistry**

What does it mean by aq excess and is this something I need to pay attention to. Does it help me balance the equation

**Chemistry**

I need help balancing this problem HClO3(aq excess) + CaCO3 I got to HCO3 + CaCiO3

**Chemistry**

Calculate the number of moles in 22.6 g C3H7OH 22.6g C3H7OH x 1 moL C3H7OH /60.11g C3H7OH = 0.375 molC3H7OH Am I right

**Chemistry**

What is the mass of 0.0065 mole of ruthenium 6.5 mol Ru x101.07g Ru/1mol Ru = 0.656g Ru Or is it 0.66g Ru

**Chemistry**

Li(s) + N2 6Li(s) + N2 ==> 2 Li3N Li =6. Li =6 N= 2. N =2 Am I correct now

**Chemistry**

Li(s) + N2 6Li(s) + N2 ==> 2 Li3N Li =6. Li =6 N= 2. N =2

**Chemistry**

I have to put the correct complete and balanced equation for Li(s) + N2(g) Li(s) +N2(g) --- LiNi2(s) I think I'm correct what do you think

**Chemistry**

What is the net ionic equation for the reaction Cu(s) + 2 Ag (NO3)2(aq) --- Cu(NO3)2(aq) + 2AG(s)

**Chemistry**

C4H10O(l) + O2(g) --- CO(g) + H2O(g) When I balanced it I got this C4H10O(I) + 4O2(g) --- 4CO(g) + 5H2O Am I correct

**Chemistry CONFUSED**

I don't want the answer. Do I have to account for the molar mass of CO2 and O2.

**Chemistry CONFUSED**

Ok I'm really confused on the question I asked how many CO2 molecules can be made with 0.500 mol of oxygen atoms. Please help with setting this up

**Math**

got it. Thanks so much.

**Math**

is that with the requirement that each couple sit side by side?

**Math**

Four couples have purchased ticket to the school play. Their sear are next to one another in a single row. If each couple sits side by side, how many seating arrangements are possible? (I came up with 24. correct??)

**Chemistry**

When the following equation is balanced with the smallest integral coefficients, the coefficient of the HNO3 is Li2CO3(s) +HNO3(aq) -- LiNO3(aq)+H2O(l)+CO2

**Chemistry HELP**

Calculate the number of molecules in 3.11 mol of CCL4 I got 2.88E26 am I correct

**Chemistry**

I don't understand how to work this problem can you help

**Chemistry**

How many CO2 molecules can be made with 0.500 mol of oxygen atoms?

**Chemistry**

Calculate the number of molecules in 3.11mol of CCL4 this is what I'm doing I got the molecular weight of CCL4 which is 181.88 Then I set it up like this 3.11 mol CCL4/ 181.88 mol CCL4 x 6.022E23 = 1.03E22 Am I right

**Chemistry**

I did Zn(2)=65.39 then I divided that by the amu of Zn(NO3)2 x 100 is that right

**Chemistry**

What is the percent zinc in Zn(NO)3 2xZn/189.41]=34.52% am I right

**Chemistry**

What is the formula mass for (NH4)3PO4

**Math**

why adding 1=I Rather then 1-i

**Chemistry Please Help**

So this is what I did 1E6kg x 1 mole Fe/55.85g= 17905 moles Fe 17905 mole Fe x 1 mol Fe2o3/2mol Fe *159.70g/1moleFe2O3* 1kg/1000= 1429kg

**Chemistry Please Help**

Iron is found in Earths crust as several different iron compounds. Calculate the mass (in kg) of each compound that contains 1.0 x 10E3 kg of iron. Fe2O3 Please help step by step

**Chemistry**

I got that as well but then I took the molar mass and divided by the empirical formula and got C8H10N4O2

**Chemistry**

Caffeine a stimulant found in coffee has the mass composition of C, 49.48%, H, 5.19%, N, 28.85%, O 16.48%. The molar mass of caffeine is 194.19g/mol. Find the molecular formula for caffeine.

**Chemistry**

I figured it out yay

**Chemistry**

Calculate the empirical formula for the compound 1.245g Ni, 5.381g I Can you help with the steps please

**Chemistry**

Calculate the mass (in kg) of each compound that contains 1.0 x 10E3 kg of iron. Fe2O3 I really can't figure this one out please help step by step

**Chemistry**

Given 2.05 mol Hg find mass Hg 2.05 mol Hg x 200.59g Hg / 1 mol Hg =411g Hg My question is would my answer be wrong if I put it in scientific notation 4.11E2

**Chemistry**

Ok thank you very much

**Chemistry**

Ok I think I'm gettingvit I hope, I need to check my work. Given 0.0449 mols Pt Find mass 0.0449 mol Pt x 195.08/1 =8.76g Pt Am I right

**Chemistry**

Confused again ok I have to find the number of atoms in carbon with a mass of 13.5. So this is what I didi. 13.5 / 12.01* 6.022 *10^23= 6.77x10^23 but the correct answer is 6.74x10^23 what have I done wrong

**Chemistry**

Ok I'm given 38.5 mg as mass. I have to find moles and number of atoms. Am I also converting mg to g? If so please help

**Chemistry**

How many moles of gold atoms do 3.45 x 10^24 gold atoms constitute. This is what I did 3.45 x 10^24 x 1 / 6.022 x 10^23 = 573 am I right

**Chemistry**

Ok what I did wrong was say 48 O atoms instead of just 3. Thank you very much

**Chemistry**

Very confused! Converting between grams of a compound and grams of a constituent element Determine the mass of oxygen in a 5.8 g of NaHCO3 5.8 g NaCHO3 * 1 mol NaCHO3/ 84.01 NaCHO3 * 48.00 mol O / 1 mol NaCHO3 * 16.00 g O/ 1 mol = I got 53 but the answer is 3.3 g O Help what a...

**Chemistry**

When I worked the question I got cu = 0.0196 and o= 0.0196 so the empirical formula is CUO

**Chemistry**

A 1.250 g sample of copper wire was heated in air and reacted with oxygen to give 1.565 g of copper oxide product. Calculate the empirical formula of the copper oxide. Please help I'm lost. I need step by step Please and thank you

**Geometry**

A 30-foot cable is suspended between the tops of two 20-foot poles on level ground. The lowest point of the cable is 5 feet above the ground. What is the distance between the two poles?

**Math**

Sorry if you spend $4 every 7 mins, in 9 days you'll spend how much

**Math**

A car covers 2924 km in 43 hrs. What is it's speed

**Chemistry**

Write the Lewis structure for each ion Al3+ Mg3+ Se2- N3- My question is why does Se2- get a bracket and 8 dots. And the same for N3-. I hope I'm making sense.

**Math**

Chris works an electrician with the Central Electric Company. He earns $16.25 per hour with time and a half after 40 hours. If he works 43 hours Monday through Friday, how much will he earn?

**Chemistry**

I don't understand what valence electrons and core electrons are. Ex: Se = 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p4 What makes 4s2 and 4p4 valence electrons and the rest core

**Science **

When a boxer has been knocked out what part of his brain has been affected?

**Science**

Rip Van Winkle was a man who slept 20 years Upon autopsy, it was found that there was structual damage to his?

**Psychology**

When a boxer is knocked out, it is believed that his _____ has been affected.

**Chemistry**

Silver has a density of 10.5 g/cm3 and gold has a density of 19.3 g/cm3. Which would have a greater mass, 5 cm3 of silver or 5 cm3 of gold

**Chemistry**

An irregular shaped stone was lowered intro a graduated cylinder holding a volume of water equal to 2.0 ml. The height of the water rose to 7.0 ml. If the mass of the stone was 25 g, what was the density

**Law**

Thanks Ms. Sue

**Chemistry**

What are the atomic number (z) mass number (a) and symbols of the carbon isotope with 7 neutrons. What is and how do I get the mass number?

**Law**

What was the real significance of the Mempa case? What is the difference between a suspended sentence and probation?

**Chemisrry**

If the specific gravity of E85 gasohol is 0.801' what is the mass of 1.00 gallon of th E85 fuel. Given 1 gallon = 3.75 liters

**Math**

A thin lead apron is used in dental offices to protect patients from harmful X rays. If the sheet measures 75.0 cm by 55.0 cm by 0.10 cm, and the density of lead is 11.3 g/ cm, what is the mass of the apron in grams?

**Chemistry**

Serine exists in its zwitterion form at a pH of 5.7. Draw the structural formula for the same. Explain the manner in which the structural formula of polar and non-polar amino acids would vary.

**marketing**

What is the best approach for marketing services such as a City's best features to attract tourism?

**english**

using atleast five different pronouns, adverbs, and adjectives, write several sentences describing a recent interaction with a friend of a "ritual" you celebrate.

**Chemistry**

A 50g sample of metal was heated to 100 degrees Celsius and then dropped into a beaker containing 50g of water at 25 degrees Celsius. If the specific heat of the metal is .25 cal/g degrees Celsius, what is the final temperature of the water? A. 27 B. 40 C. 60 D. 86 (units are ...

**physics**

In a solar water heater, energy from the Sun is gathered by water that circulates through tubes in a rooftop collector. The solar radiation enters the collector through a transparent cover and warms the water in the tubes; this water is pumped into a holding tank. Assume that ...

**Finance**

A three-year bond has 8.0% coupon rate and face value of $1000. If the yield to maturity on the bond is 10%, calculate the price of the bond assuming that the bond makes semi-annual coupon interest payments.

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