Sunday
February 7, 2016

# Homework Help: Science: Chemistry

## Recent Homework Questions About Chemistry

Chemistry
6.00 g of NaOH are dissolved in water to make 4.00 L of solution. What is the concentration of hydronium ions, [H3O+], in this solution?
Saturday, July 25, 2015 by Serge

chemistry
find the molar mass of 7.5gm of a gas occupying 5.8 lt volume at s.t.p.
Saturday, July 25, 2015 by nidhi

chemistry
Epsom salts, a strong laxative used in veterinary medicine, is a hydrate, which means that a certain number of water molecules are included in the solid structure. The formula for Epsom salts can be written as MgSO4 · x H2O, where x indicates the number of moles of H2O ...
Thursday, July 23, 2015 by Tutakumbo

science: chemistry
How many moles of NaOH must be added to 1.0 L of 2.6 M HC3H5O3 to produce a solution buffered at each pH? 1)pH= 4.28 2)pH=pKa
Thursday, July 23, 2015 by Julie

science: chemistry
A buffered solution is made by adding 47.4 g C2H5NH3Cl to 1.00 L of a 0.68 M solution of C2H5NH2. Calculate the pH of the final solution. (Assume no volume change. Assume that all solutions are at 25°C.)
Thursday, July 23, 2015 by Julie

chemistry
is gravimetric analysis or colourimetry more accurate when it comes to precipitation reactions where only around 6g and 100ml of the products are used?
Thursday, July 23, 2015 by Kendall

Physics/ Chemistry
The carbon isotope 14C is used for carbon dating of objects. A 14C nucleus can change into a different kind of element, a neighbor on the periodic table with lower mass, by emitting a beta particle – an electron or positron – plus a neutrino or an anti-neutrino. ...
Wednesday, July 22, 2015 by Anonymous

Chemistry
The activation energy (E*) for a reaction is 195 KJ. If the k for this reaction is 3.46 x 10-5/min at 35oC, what will the temperature be in OF when k is 1.5 x 10-3/min?
Wednesday, July 22, 2015 by Jessica

chemistry
5.85gm of NaCl is dissolved in water and the solution is made up to 0.5 litre. what is the molarity of solution ????
Wednesday, July 22, 2015 by Anonymous

Chemistry
when are you going to use the water displacement method in taking the volume of the object?
Wednesday, July 22, 2015 by Sheena

Chemistry
You mix 45 ml of .20M HCl with 45 ml of .20M KOH in a calorimeter. The temperature of both reactions before mixing is 21.5oC. The temperature rises for the mixture to 22.7oC after mixing. What is the enthalpy change per mole of water produced?
Wednesday, July 22, 2015 by Jessica

Chemistry
What is the heat capacity of 83 g of mercury? Specific heat of mercury = 0.14 J/(g oC)
Tuesday, July 21, 2015 by Mindy

Chemistry
What is the mass, in grams, of a sample of solid zinc if its temperature changes from 25.7oC to 39.0oC when it absorbs 123 J of heat energy? Specific heat of zinc = 0.388 J/(g oC)
Tuesday, July 21, 2015 by Mindy

Chemistry
How many grams of Fe can be heated from 40.0oC to 60.0oC when 20.0 g of Cu cools from 100.0oC to 25.0oC? Specific heat of Fe = 0.444 J/(g oC); specific heat of Cu = 0.382 J/(g oC)
Tuesday, July 21, 2015 by Mindy

Chemistry
Calculate the amount of heat, in kJ, needed to convert 30.0 g of ice at -5.2 oC to liquid water at 58 oC. Specific heat of ice = 2.10 J/(g oC); heat of fusion of ice = 334 J/g; Specific heat of water = 4.18 J/(g oC)
Tuesday, July 21, 2015 by Mindy

Chemistry
If the rate of the reaction is 3.5 x 10-3 at 330 K, and the rate of reaction at 285 K is 5.2 x 10-5 what is the activation energy Ea in KJ/mole?
Tuesday, July 21, 2015 by Jessica

Chemistry II
How many grams of gasoline would you need to burn if you started with a 275 gram piece of ice that started at -25 OC and by the end of the experiment had 100 grams of steam and the rest liquid water?
Tuesday, July 21, 2015 by Cynthia

Chemistry
For a given reaction, the rate constant doubles when the temperature is increased from 27 o C to 49 o C. What is the activation energy?
Tuesday, July 21, 2015 by Melissa

Chemistry
Would gravimetric analysis or colorimetry be more accurate when calculating the percentage yield of a precipitate?
Tuesday, July 21, 2015 by Chiara

chemistry
Arrange the following aqueous solutions in order of decreasing freezing points (lowest to highest temperature): 0.10 m Na3PO4, 0.35 m NaCl, 0.20 m MgCl, 0.15 m C6H12O6 and 0.15 m CH3COOH.
Monday, July 20, 2015 by Natalie

Chemistry
How many milliliters of .200 M NaOH solutions are needed to react with 40.0 mL of a 0.340 M NiCl2 solution? Equation: NiCl2(aq) + 2NaOH(aq) --> Ni(OH)2(s) +2NaCl(aq)
Monday, July 20, 2015 by elle

chemistry
A 8.75-L container holds a mixture of two gases at 23 °C. The partial pressures of gas A and gas B, respectively, are 0.317 atm and 0.755 atm. If 0.100 mol of a third gas is added with no change in volume or temperature, what will the total pressure become?
Monday, July 20, 2015 by sam

Chemistry
25cm^3 H2SO4 is neutralized by 40 cm^3 of 0.03 mol/dm^3 KOH. What is the molar concentration of H2SO4?
Monday, July 20, 2015 by Sarah

Chemistry
9. If 5.40 kcal of heat is added to 1.00 kg of water at 100⁰C, how much steam at 100⁰C is produced? Show all calculations leading to an answer.
Monday, July 20, 2015 by Tisha

chemistry
A 30.0 g sample of water at 10.0°C is mixed with 50.0 g of water at 57.0°C in a calorimeter. Calculate the final temperature of the mixture
Monday, July 20, 2015 by robert

organic chemistry
what is the principle involved in the detection of phosphorus? the visible result of it is canary yellow
Sunday, July 19, 2015 by Anonymous

Organic Chemistry
Consider the weak organic base n-propylamine. The Kb value for this base is 1.3-10^-5, and its pKa is 10.6. At what pH are the "proton on" and "proton off" forms present in equal concentrations? At what pH values would the "proton on" form have ...
Sunday, July 19, 2015 by Lily

science, chemistry
"You run out of brown sugar and decide to use only granulated sugar instead. The cookies come out much thinner than usual. Design a controlled experiment to test your hypothesis *, describing how you would interpret your results. Please limit your response to one ...
Sunday, July 19, 2015 by llau

organic chemistry
How will i know if the r group's common name is tert-pentyl or sec-penytl? What is the difference between sec and tert?
Sunday, July 19, 2015 by Anonymous

Chemistry
You pass a road sign saying "New York 112 km." If you drive at a constant speed of 65 mi/h, how long should it take you to reach New York? If your car gets 28 miles to the gallon, how many liters of gasoline are necessary to travel 112 km?
Saturday, July 18, 2015 by Chen

chemistry
calculate the pH. A solution is formed mixing 12.0 mL of .120 M HBr with 22.0mL of .180 M HCl
Friday, July 17, 2015 by ellena

chemistry
in our notes for strengths of acids and bases it says that you could add a strong/weak acid with a strong/weak base and it will give you a low, medium or high delta h. so wouldn't acids and bases be related to thermochemistry?
Thursday, July 16, 2015 by will

Chemistry
If 2.64g of CO2 dissolves in 500ml water at 25°C, what is the Kh(Henry's law constant) for CO2? The total pressure is 3340 mmHg and air pressure at 25°C is 680 torr.
Thursday, July 16, 2015 by Jake

science
write aout chemistry
Thursday, July 16, 2015 by bhawana bhusal

chemistry
how much volume of oxygen at stp in litres is required to burn 4g of methane gas completely
Wednesday, July 15, 2015 by sweety

chemistry
How many grams of sucrose are in 1.5kg of a 10.5% (by mass) solution of sucrose?
Wednesday, July 15, 2015 by vicki

Chemistry
A sodium hydroxide sample is contaminated with sodium chloride. A 0.240 gram sample of this impure sample is dissolved in water and titrated with 21.50 mL of 0.130 M H2C2O4. Calculate the percent sadium hydroxide in the impure sample [(mass of NaOH in impure sample/mass of ...
Wednesday, July 15, 2015 by Sam

college chemistry
A 9.60 mL sample of 12.0 M HCl is used to prepare 125 mL of diluted acid. A sample of 32.4 mL of Ba(OH)2 base is exactly neutralized by 24.0 mL of dilute acid. What is the concentration of the Ba(OH)2 base? Help. I don;t know where to start.
Wednesday, July 15, 2015 by sara

Chemistry
If 32.6 mL of 0.240 M oxalic acid are required to titrate 48.9 mL of unknown sodium hydroxide: How many moles of acid are used in the titration? How many moles of base are used in the titration? What is the molarity of the unknown NaOh base? Please help I do not know where to ...
Wednesday, July 15, 2015 by sarah

chemistry
Wednesday, July 15, 2015 by jacky

Chemistry
a) Determine how many molesof I3 are produced by 1 mole of Cu(IO3)2. b)Determine the stoichiometric ratio between iodate and thiosulfate. c)Determine the molar solubity expression for Cu(IO3)2 For C) I got ksp=[Cu2+][IO3-]^2 Is this correct?

chemistry
how we prepare a 4M solution of NaCl in 100ml and after this we dillute this 4ml solution to make3.8M solution.
Tuesday, July 14, 2015 by nisha

Chemistry
How many moles of gas must be forced into a 5.2 L tire to give it a gauge pressure of 30.6 psi at 26 ∘C? The gauge pressure is relative to atmospheric pressure. Assume that atmospheric pressure is 14.9 psi so that the total pressure in the tire is 45.5 psi .
Tuesday, July 14, 2015 by Cici

organic chemistry
what is the principle involved, practical application, examples of the process in chromatography?
Tuesday, July 14, 2015 by Coleen

Chemistry
If your car gets 28 miles to the gallon, how many liters of gasoline are necessary to travel 112km? I need the answers so badly. Thank you very much.
Tuesday, July 14, 2015 by Chen

chemistry
What would be the pH of a solution that liberates carbon dioxide from sodium carbonate. Give chemical equation and reason
Tuesday, July 14, 2015 by clive

Chemistry
A student collected the following data for a fixed volume of gas: ￼Temperature (C) Pressure (mm of hg) 10 726 20 750 40 800 70 880 100 960 150 ??? Fill in the missing data point. Show all calculations leading to an answer.
Monday, July 13, 2015 by Maria

Chemistry/Physics
How much heat is required to raise the temperature of 100 g of lead 20 degrees C? The specific heat of lead is 0.0305 cal/g K. A) 51 cal B) 61 cal C) 71 cal D) 81 cal
Monday, July 13, 2015 by Domino

chemistry
a thermometer containing 9.5g of mercury has broken. If Mercury has a density of 13.6g/ml what volume spilled
Sunday, July 12, 2015 by Paula

CHEMISTRY HELP
how many hao's exhibited by S16? my answer is 4?
Saturday, July 11, 2015 by Sofia

organic chemistry
Is 4 ethyl-2,4 octadiene a correct name? How can i identify if it's incorrect or correct?
Saturday, July 11, 2015 by Lesley

organic chemistry
isobutyl tert pentyl acetylene has how many hyrogen atoms? iso=2 butyl=4 tert=4 pentyl=5 acetylene=2 28 h atoms? can you please teach me how to compute hydrogen atoms.. Neoheptane has how many atoms?
Saturday, July 11, 2015 by Erika

organic chemistry
evaluate the number of carbon for the ffg. pairs by writing G if greater, L if less than or E if equal 1. butene E sym dimethylethylene sol'n: butene has 4 carbons and sym dimethylethylene also has 4 carbons so it's equal. Am i right? 2. methylbutane L isopentane ...
Saturday, July 11, 2015 by Erika

chemistry
How can I determine the concentration of HCl remaining in the flask after back titration? PLEASE SHOW SOLUTION!!!!!! Con. of HCl: 0.14M Volume added:100mL Con. of NaOH:0.145M Weight of Tablet: 1.0g I have been given weight of antacid, concentration and volume of HCl and ...
Saturday, July 11, 2015 by Jane Smith

Chemistry
Prepare 250ml of 0.2M phosphate buffer of pH 6.4.starting from Na2HPO4,NaH2PO4,0.129N NaOH solution.
Friday, July 10, 2015 by Rita

chemistry
Zinc is to be used as an internal standard for the polarographic analysis of thallium. A standard solution containing twice the concentration of zinc as thallium has diffusion currents of 1.89 microAmps for thallium and 3.5 microAmps for zinc. A 10.0g sample of an alloy ...
Friday, July 10, 2015 by Adeola

Orgnic chemistry
Some molecules w/ non polar bonds like C-S and C-I when exposed to a highly polar environment may assume polarity -Due to vacant d orbitals of S (i dont get this. So if it has a lot of vacant orbitals it will be polar?) -big atomic radius of I (please explain this to me) S and...
Friday, July 10, 2015 by jane

chemistry
The polarogram for 20ml solution that was 3.65 x 10^-3 M in cadmium (Cd2+) gave a wave for that ion with a diffusion current of 31.3microampere. Calculate the percentage change in concentration of the solution is the current in the limiting current region were allowed to ...
Friday, July 10, 2015 by Adeola

chemistry
1. Which example has particles that can be drawn closer to occupy smaller volume? a. fruit juice b. block of wood c. air inside the syringe d. ice cube 2. Which of the following phenomena does NOT involve the application of gas pressure? a. burning fuels b. falling leaves c. ...
Friday, July 10, 2015 by ken

chemistry
A 250 mL sample of gas at 1.00 atm and 20oC has the temperature changed to 40oC and the volume changed to 500 mL. What is the new pressure?
Thursday, July 9, 2015 by Anonymous

Chemistry
Why is the rate determining step the slowest step?
Thursday, July 9, 2015 by Alex

Chemistry
The hydroxide ion reacts with the H2PO2 ion according to the following equation: OH^- + H2PO2^- > HPO2^-2 + H2 The rate law for this reaction rate is R=k[OH^-]^2[H2PO^-2]. What will be the change in the reaction rate if the H2PO2 ion concentration is doubled. What will the ...
Thursday, July 9, 2015 by Anonymous

chemistry
The synthesis of a certain drug can be carried out with 91.7% yield. In one experiment 14.8 g of the drug was obtained. What was the theoretical yield for this experiment?
Thursday, July 9, 2015 by Linda

Chemistry
How is the enthalpy change for a reaction related to the enthalpy of the reactants and products? Is it that the enthalpy for the reactants and products equals the enthalpy change for the reaction?
Thursday, July 9, 2015 by Anonymous

Chemistry
What is the octet rule? How does the rule explain the common ion of fluorine and of calcium? The octet rule is when an element contains 8 valence electrons. The rule explains the common ions of fluorine and calcium to show how much is needed to gain/lose electrons to get that ...
Thursday, July 9, 2015 by Sam

chemistry
. An enzyme-catalyzed reaction was carried out in a 0.2M �Tris� buffer, pH 7.8. As a result of the reaction, 0.03 mole/liter of H+ was produced. (pKa of Tris =8.1) (a) What was the ratio of Tris+ (conjugate acid) / Triso (Conjugate base) at the start of the ...
Thursday, July 9, 2015 by pankaj

Chemistry
If the electromagnetic radiation used to send television signals have a frequency of 3.0 * 10^9 Hz, what is its wavelength? I forget how to do a problem like this. Just taking a guess, is this somewhat a conversion equation?
Wednesday, July 8, 2015 by Jack

Chemistry
What volume, in liters, of 1.04 M KOH solution should be added to a 0.116 L solution containing 10.08 g of glutamic acid hydrochloride (Glu, FW = 183.59 g/mol; pKa1 = 2.23, pKa2 = 4.42, pKa3 = 9.95) to get to pH 10.15?
Wednesday, July 8, 2015 by K

Chemistry
What is the catalyst of N2(g)+3H2(g) to give(double arrow) 2NH3(g)?
Wednesday, July 8, 2015 by Omoniyi Ayodeji

Chemistry
For an equation N2(g)+3H2(g) double arrowed to give 2NH3(g) what is the catalyst?
Wednesday, July 8, 2015 by Omoniyi Ayodeji

chemistry
If a 0.01M Mn(NO3)2 solution has an ammonia concentration of 6.0M, would a precipitate form? Calculate the ion product and compare to Ksp.
Wednesday, July 8, 2015 by jojo

chemistry
Treatment with sodium borohydride converts aldosterone A in to an optically inactive alditol. Ruff degradation of A from B, whose alditol is optically inactive. Ruff degradation of B from D - glycerol dehydration. Identify A and B. Please help urgently. Please!!!!!
Wednesday, July 8, 2015 by sanjay

chemistry
at what ratio should I titrate sterile water with 50% MgSO4 to get 20% MgSO4.i mean the units of water to those of MgSO4
Wednesday, July 8, 2015 by myk

Chemistry
What is the volume occupied by 12.9 g of argon gas at a pressure of 1.30 atm and a temperature of 318 K ?
Wednesday, July 8, 2015 by Dustin

Chemistry
How does the kinetic-molecular theory help explain the difference between solids, liquids, and gases? I don't know how to really answer this question because the theory only talks about gases, unless I am looking at the wrong one. I tried to look it up swell and all I got ...
Wednesday, July 8, 2015 by Jack

chemistry
Treatment with sodium borohydride converts aldosterone A in to an optically inactive alditol. Ruff degradation of A from B, whose alditol is optically inactive. Ruff degradation of B from D - glycerol dehydration. Identify A and B.please give satisfactory answer
Tuesday, July 7, 2015 by sanjay

Chemistry-History-ish
Describe 3 experiments, run prior to 1930, and the types of energies/particles used to probe the structure of the atom. What did each experiment investigate? Include the names of the scientists associated with each experiment in your answer Would this be right? Prior to 1930, ...
Tuesday, July 7, 2015 by Anonymous

Chemistry
When naming a molecular compound, such as CO, would I write it as mono carbon monoxide or carbon monoxide? My textbook has the rule written as prefix+1st element prefix+2nd element, but I am not sure if the mono applies to the carbon or not.
Tuesday, July 7, 2015 by Jack

Chemistry
Explain the basic format and the steps needed to name an ionic compound composed of a cation that has a possibility of existing in more than one oxidation state. Is this right: There are four prefixes used when naming ionic compounds: per__ate, -ate, -ite, and hypo__ite. ...
Tuesday, July 7, 2015 by Chris

chemistry
The edge length of face centered unit cubic cell is 508pm.if the radius of the cation is 110 pm,the radius of anion is
Tuesday, July 7, 2015 by tanya

Chemistry
How much heat is needed to convert 10g ice to 10g water vapor?
Tuesday, July 7, 2015 by Drew

Chemistry
Diatomic O2 can react with the element magnesium to form magnesium oxide (MgO). The balanced chemical equation is: If 4 moles of magnesium totally reacted with more than enough O2, how many moles of MgO would be expected to form?
Tuesday, July 7, 2015 by Anonymous

chemistry
Treatment with sodium borohydride converts aldosterone A in to an optically inactive alditol. Ruff degradation of A from B, whose alditol is optically inactive. Ruff degradation of B from D - glycerol dehydration. Identify A and B
Tuesday, July 7, 2015 by sanjay

chemistry
A piece of iron (Cp = 0.450 J/(gi°C)) that has a mass of 21.5 g and an initial temperature of 100.0°C is submerged in X g of water (Cp = 4.184 J/(gi°C)) at 20.0°C. The temperature of the system (iron and water) changes to 21.4°C. What is the value of X?
Tuesday, July 7, 2015 by ken

chemistry
Consider the following reagents: zinc, copper, mercury (density: 13.6 g/mL), silver nitrate solution, nitric acid solution. a. Given a 500-mL Erlenmeyer flask and a balloon can you combine two or more of the foregoing reagents to initiate a chemical reaction that will inflate ...
Tuesday, July 7, 2015 by kate

Chemistry
Give an example of one polyatomic cation and one polyatomic anion. Show how these ions combine to make a compound. My thinking: Cation-ClO Anion-K How they form, I don't know?
Monday, July 6, 2015 by Isaac

Chemistry
What would the partial pressure of hydrogen in the gas collection tube be if the water in the tube was 25.0 mm above the water level in the beaker, the room pressure was 655 mm Hg, and the temperature of the room was 22 degrees C?
Monday, July 6, 2015 by Jenny

Chemistry
When is the term, formula unit, useful? Is it when trying to figure out the empirical formula?
Monday, July 6, 2015 by Isaac

Chemistry
What are the pros and cons of using the lewis structure? What I have so far is that it shows the shape of the compound.
Monday, July 6, 2015 by Anonymous

Chemistry
How many moles are there in 0.7g of CFC's
Monday, July 6, 2015 by Fida

Chemistry
A 150.0 mL sample of a 1.50 M solution of CuSO4 is mixed with a 150.0 mL sample of 3.00 M KOH in a coffee cup calorimeter. The temperature of both solutions and the calorimeter was 25.2°C before mixing and 31.3°C after mixing. The heat capacity of the calorimeter is 24...
Monday, July 6, 2015 by Richard

physical sciences(chemistry)
Explain why solution turns blue by referring to the relative strength of oxidising agent?
Monday, July 6, 2015 by Xalati

chemistry
1. Which example has particles that can be drawn closer to occupy smaller volume? a. fruit juice b. block of wood c. air inside the syringe d. ice cube 2. Which of the following phenomena does NOT involve the application of gas pressure? a. burning fuels b. falling leaves c. ...
Monday, July 6, 2015 by ken

Chemistry
Heat is applied to an ice cube in a closed container until only steam is present. Draw a representation of this process. What happens to the size of the molecules and total mass of the sample?
Monday, July 6, 2015 by Person

Chemistry-Molecular models
Select a compound and explain the advantages and disadvantages of using ball-an-stick, space-filling, and lewis structure to represent compound. What I have so far: The advantages for all the models are that you can see the shape of the atoms, but unlike the ball-and-stick and...
Sunday, July 5, 2015 by Anonymous

Chemistry
Explain how the formulas for H2O and NaCl provide different information about the composition of these two compounds. What I think: For every 1 atom of oxygen, there are 2 atoms of hydrogen. For every one atom of sodium there is one atom of chlorine.
Sunday, July 5, 2015 by Anonymous

Chemistry
A student mixes 764 mL of water and 476 mL of 1.00 x 10-5 M orange food dye solution. What is the concentration of this new dilute solution of orange food dye?
Sunday, July 5, 2015 by George

emmanuel college
Chemistry A is a solution of H2SO4 containing 2.5g in 500cm3
Sunday, July 5, 2015 by gboyega

chemistry
describe how you would prepare 500mL of 0.25 M NaNO3 solution?
Saturday, July 4, 2015 by siti

Chemistry
Propose three models that explain Thomson’s findings and evaluate them. To be complete you should include Thomson’s findings.
Saturday, July 4, 2015 by Kristina