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Homework Help: Science: Chemistry

Recent Homework Questions About Chemistry

Chemistry
The density of a sample of F2(g) is 1.559 g/L. If the gas is held at 755 torr, calculate the temperature. how would i calculate the volume to use

Chemistry
Wat is the product of Mn^+2 + NH3? is it Mn(NH3)2?

Chemistry
4.12 grams of Zinc are placed in a crucible with 3.00 grams (excess) of Sulfur. when reaction is complete the product mass is 6.10 grams. What mass of Sulfur should be used in the simplest formula calculation? Find the empirical formula of Zinc Sulfide. My work... 6.10 g ...

Chemistry
Cynthia combines 1.7 grams of Silver hydroxide with 234 ml of a 1.2 M solution of HBr. Assume all the silver hydroxide dissolves once it is in solution(which is technically not the case, but for this example, just go with the flow of it). What will be the final pH of the ...

Ap Chemistry
Saccharin has a pKa of 2.32 It has a formula of HNC7H4SO3 If you dissolve 4.6 grams of saccharin in 478 ml of water, what is the resulting pH ?

Chemistry
What is the volume of the oxygen produced when 1.00L carbon dioxide reacts with 20.0 g of Na2O2 based on the following unbalanced reaction at 25C and 2.00 bar? Na2O2 + CO2 -> O2 + Na2CO3 R = 0.083145 L bar K-1 mol-1 I got 1.57L but the answer is 500mL

Basic Chemistry
A 150L water heater is set to a cutoff temperature of 49 degrees C and that the incoming water is at 298K, calculate the energy in kJ needed to get this 150L water to it's maximum temperature. Please help!

Chemistry
Is the flame coloration a test for the metal or for the acid radical?

Chemistry
if I want to show the results of a nitrate analysis as nitrogen what is the equation

chemistry
How many GRAMS of carbon dioxide can be produced from 3.70 grams of oxygen ?

Chemistry
Similar question to http://www.jiskha.com/display.cgi?id=147​4753951 "If that 22.33g sample of calcium chloride was dissolved in 1000.0g of water, with both substances originally at 25.0C, what would be the final temperature of the solution be? Assume no loss of heat to ...

Chemistry
Please help...entrance exam soon Write the oxidation and reduction half reactions(showing e- lost or gained) for the foll O3 + I- -> IO3- + O2 (acidic)

Organic Chemistry
What would happen to the melting point of a solid if it is mixed with granular particles of glass? Explain.

Chemistry
Andrew weighs 45 lbs and requires insulin. His doctor has prescribed 0.150 units of insulin/kg body weight/hr while he is in the hospital. The insulin bottle you have possesses a concentration of 20.0 units/15.0 ml and all must be given. Give all answers to three sig figs. a. ...

Chemistry
CaCl2(s) -> Ca(aq) + 2Cl(aq) ΔH_rxn = +198.0 KJ "If that g sample of calcium chloride was dissolved in 1000.0g of water, with both substances originally at 25.0C, what would be the final temperature of the solution be? Assume no loss of heat to the surroundings and ...

Chemistry
Five year old Andrew weighs 45 lbs and requires insulin. His doctor has prescribed 0.150 units of insulin/kg body weight/hr while he is in the hospital. The insulin bottle you have possesses a concentration of 20.0 units/15.0 ml and all must be given. Give all answers to three...

Chemistry
The pressure in pressure cooker is 1.90 what will be the temperature

Chemistry
Aqueous solutions of copper (II) sulfate, CuSO4, and potassium carbonate, K2CO3, a blue parcipitate of copper (II) carbonate forms in addition to one other compound. We have to write the balanced chemical equation for that but our teacher didn't teach us anything about that

CHEMISTRY HELP
Reaction: 1/2N2 + 3/2H2 --> NH3 Delta H = -46Kj/mol 1) Find delta H n(NH3)formed=5 mol. M(NH3=8.5g) 2) Find delta H a)3 mol H2 + 3 mol N2 b) 3 mol H2 + 0.5 mol N2 M NH3 = 17 g/mol ???

Chemistry (Help!)
Reaction: 1/2N2 + 3/2H2 --> NH3 Delta H = -46Kj/mol 1) Find delta H n(NH3)formed=5 mol. M(NH3=8.5g) 2) Find delta H a)3 mol H2 + 3 mol N2 b) 3 mol H2 + 0.5 mol N2 M NH3 = 17 g/mol ???

chemistry
A solution contains a mixture of pentane and hexane at room temperature. The solution has a vapor pressure of 252 torr . Pure pentane and hexane have vapor pressures of 425 torr and 151 torr, respectively, at room temperature. What is the mole fraction of hexane? (Assume ideal...

chemistry
If 10.0 L of butane and oxygen are combined at the same temperature and pressure, which gas will be left over after reaction? Include your calculation/reasoning.

Chemistry
to determine the concentration of ascorbic acid in fruit juice using DCPIP

chemistry
A solution contains naphthalene (C10H8) dissolved in hexane (C6H14) at a concentration of 11.07 % naphthalene by mass. Calculate the vapor pressure at 25 ∘C of hexane above the solution. The vapor pressure of pure hexane at 25 ∘C is 151 torr.

chemistry
Paper pulp is sold on the basis that it contains 12% moisture; if the moisture exceeds this value, the purchaser can deduct any charges for the excess moisture and also deduct for the freight costs of the excess moisture. A shipment of pulp became wet and was received with a ...

Chemistry
An element has three stable isotopes. One has a mass number of 63 and an abundance of 50%. The second has a mass number of 65 and an abundance of 30%. The third has a mass number of 67 and an abundance of 20%. Calculate the relative atomic mass of this element. I am so ...

chemistry
A sample of CaCl2⋅2H2O/K2C2O4⋅H2O solid salt mixture is dissolved in ~150 mL de-ionized H2O. The oven dried precipitate has a mass of 0.253 g. The limiting reactant in the salt mixture is K2C2O4⋅H2O. Determine Mass of K2C2O4⋅H2O(aq) in Salt Mixture in ...

chemistry
In a large building, oil is used in a steam boiler heating system. The combustion of 1.0 lb of oil provides 2.2×107J. Part A How many kilograms of oil are needed to heat 110 kg of water from 24 ∘C to 100∘C? (Assume that 1lb=454g, the specific heat of liquid water ...

Chemistry
Given a 800 mg sample of Thorium-231 decomposes via beta emission with a half life of 25.5 hours, how long would it take, in days, for the sample to decay down to 25 mg? 231 0 231 Th -> Beta + Pa 90 -1 91 800 mg/ 25 mg

Chemistry
The efficacy of certain drugs is affected by pH. Many drugs are absorbed into the blood through cells lining the stomach or the small intestine by direct diffusion across the plasma membrane. Since the interior of the plasma membrane is hydrophobic, uncharged molecules cross ...

chemistry
Bicine is an amino acid, but not a building block of proteins. Rather, it is a reagent commonly used in the biochemistry laboratory. Bicine contains two ionizable groups: tertiary amine (pKa 8.3) and carboxyl (pKa 2.3) a. For each of the ionizable groups in bicine, draw its HA...

chemistry
You discovered a new diprotic acid, which you have named edmontonic acid. You want to characterize the pKa’s of edmontonic acid, so you perform a titration experiment. Your data are summarized in the table below. Your titration sample contains 150 mmol of edmontonic acid. ...

chemistry
In a titration of malic acid, what is the pH after: a. 0.75 molar equivalents of NaOH have been added? 1 b. 1.30 molar equivalents of NaOH have been added?

Organic Chemistry
One sample that is 1mm in height has a melting point range of 200-201. What would be the melting point range of a 10mm sample in height if both samples heating rate is 2 degrees Celsius per minute? I'm thinking it would be about 2000-2010 but I'm not fully sure. I used algebra...

Chemistry
How many grams of ammonia are needs to produce 0.5kg of NH42So4

chemistry
is this statement true? More heat is needed for vaporization of a liquid compared with melting a solid of the same substance.

chemistry
If you transfer 5 J of energy to 1 g water and to 1 g ethanol, each starting at the same temperature which would have a higher temperature at the end? Water or ethanol? or will they have the same temperature at the end?

Chemistry
18cubic centimeters of 0.8Mlithium hydroxide is neutralized by 24cubic centimeters of 0.3Msulphuric acid.What is the formular of the salt formed?

Chemistry
20cubic centimeters of 0.27M sodium hydroxide solution is added to 18.2cubic centimeters of 0.75M hydrochloric acid.To the solution is then added excess magnesium.What volume of hydrogen gas measured at s.t.p evolved?

Chemistry
84cubic centimeters of hydrogen chloride gas measured at s.t.p is dissolved in water and titrated with 0.15M sodium hydroxide.What volume of sodium hydroxide solution is required for complete neutralization?

Chemistry
how many cubic cm hydrogen chloride gas at s.t.p would be required to precipitate all the silver ions from 32 cm of 0.08 M silver nitric solution?

Chemistry
What volume of ammonia gas at s.t.p is required to neutralise 40 cm of 2 M sulpheric acid?

Chemistry
8.4 g of a mixture of potassium hydroxide and potassium chloride were made up of 1 litre of aqueous solution. 20 cm of this solution required 24.2 cm of 0.1 m nitric acid for neutralisation. calculate the percentage by mass of potassium chloride in the mixture

Chemistry
If 100.0 mL of 0.171 M Na2SO4 are added to 100.0 mL of 0.889 M Pb(NO3)2, how many grams of PbSO4 can be produced? Equation: Na2SO4 + Pb(NO3)2 = 2NaNO3 + PbSO4

Chemistry
(DrBob222 please help me) What would be the final temperature of the system if 16.6 g of lead at 138 ◦C is dropped into 23.4 g of water at 8.68 ◦C in an insulated container? The specific heat of lead is 0.128 J/g◦C. Please explain with the numbers plugged in ...

Chemistry
PLEASE HELP OR I WILL FAIL What would be the final temperature of the system if 16.6 g of lead at 138 ◦C is dropped into 23.4 g of water at 8.68 ◦C in an insulated container? The specific heat of lead is 0.128J/g◦C.

Chemistry G.12
Check if im right please: 4NH3(g) + 5O2(g) → 4NO(g) + 6H2O(g) At a specific time in the reaction, ammonia is disappearing at rate of 0.068 mol/(L • s). What is the corresponding rate of production of water? I did Rate of Production H20 = 1/6(0.068) = 0.0113 mol/(L*s) ...

Physical Science/ Chemistry
Which of the following shows the correct order of Family #1 elements from least to most reactive? A) Li, Na, Rb, K B) Li, Na, K, Rb C) Rb, K, Na, Li D) Li, Na, K, Ba

AP Chemistry
(DrBob222 please help me) A sample of 1.97 grams of Z is dissolved into 500 grams of water which is in a styrofoam coffee cup. The temperature is monitored and is found to rise from 25.015◦C to 25.484◦C. What is ∆Hsolution for substance Z? Assume no heat is ...

Chemistry
Hey, can someone help me with this? A compound containing only C, H and O was subjected to combustion analysis. A sample of 6.120×10^-2 g produced 1.601×10^-1 g of CO2 and 5.243×10^-2 g of H2O. Determine the empirical formula of the compound and enter the ...

Chemistry
Trying to wrap my head around this, thanks for the help: You have 8.63 moles of C2H6O2 in the following unbalanced equation: (I already balanced it, here is the balanced): C2H6O2 + 5 O2 → 4 CO2 + 6 H2O How many moles of water are produced in this reaction?

chemistry
Is the following sentence true or false? The value of an error must be positive.

analytical chemistry
Calculate the concentration of the initial nitrate stock solution (in ppm) if exactly 0.361 g of KNO3 is dissolved in a 1 L volumetric flask with distilled water. Here I want the concentration of nitrogen in ppm.

Chemistry
For a reaction N2+O2=2NO If Kc=10-30 at 25°C One Can predict with solid reason? (1) More NO is formed (2) The forward reaction goes to completion (3) The backward reaction goes to completion (4) More reactant can consumed

Chemistry
For a reaction N2+O2=2NO If Kc=10-30 at 25°C One Can predict (1) More NO is formed (2) The forward reaction goes to completion (3) The backward reaction goes to completion (4) More reactant can consumed

Chemistry
So I have to find the % by mass of an unknown metal that reacted with HCl to create MCl2 (with the M being unknown). Then I need to determine identity of the missing metal. I know that the final mass of the compound MCl2 is 12.47g and that the original mass of the metal M ...

Chemistry
how would you prepare 250 mL solution containing the following: 0.30 M mannitol, 0.025 M phosphate buffer pH 7.5? You are given solid mannitol, kh2po4, and k2hpo4. (pKa=6.86)

Chemistry
How would NaHCO3 dissociate in water for a beaker diagram? Would it be Na+ and HCO3-

Chemistry
When you mixand separate CaCO3 and SiO2 with acetic acid-vinegar, it is a chemical reaction. It bubbles and CO2 is produced. What property of CaCO3 causes this to happen? Could you explain this to me pls. I am guessing the acetic acid reacts with one of the acetic acid, but ...

Organic chemistry
An unknown compound (x) melts at 60°C and is mixed with a compound (y) that melts at 45°C and is soluble in x. Will the Melting point for the mixture start below 45°? I think so, because if you look at ice and salt for an example, salt has a way higher melting point than ...

analytical chemistry
Calculate the concentration of the initial nitrate stock solution (in ppm) if exactly 0.361 g of KNO3 is dissolved in a 1 L volumetric flask with distilled water.

chemistry
6 cm/sec to mph i got 9.664mph

Chemistry
The solubility of copper sulphate at 0 C

maths
In a class of 60 students, the number of students who passed biology is 6 more than the number who passed chemistry. Every student passed at least one of the two subjects and 8 students passed both subjects. I) how many students passed biology? ii) how many students passed ...

chemistry
How many grams of fe is present in 30g of FeSO4

College Chemistry
Determine the concentrations of MgCl2, Mg2+, and Cl- in a solution prepared by dissolving 2.39 x 10^-4g MgCl2 in 2.50L of water. Express all three concentrations in molarity. Also display the concentrations of ionic species in part per million (ppm).

chemistry
How many mL of 0.6 M H2SO4 solution are needed to react completely with 23.62 g of Fe2O3 in the following reaction?

Chemistry AP
The equilibrium constant for the formation of phosphorus pentachloride is 1.9. If the partial pressure of each gas is 0.5 atm, will the reaction (as written) proceed forward or backward to reach equilibrium? PCl3(g) + Cl2(g) PCl5(g) A. Forward, because K is greater than Q B. ...

chemistry
2NO+O2->2NO2 a) During a certain interval of time the variation of oxygen O2 moles is -5mol. Calculate the variation of the number of moles of nitrogen monoxide NO and that of nitrogen dioxide NO2 during the same interval of time. b) The duration during which the variation ...

science chemistry
balance Redox :- CuS + SO4²- = CuO+SO2

Chemistry
How many grams of CO2 is produced from 855 grams of C6H12O6 in the process of cell respiration? Please further discuss the solution on how to get convert the mols of glucose to mols of CO2. Thank you.

Chemistry
You have to work with 240 mL of a liquid. You are provided with 250 mL, 400 mL and 800 mL beakers. Which would be the best size of beaker to use? Which would be the worst size? Explain your reasoning. A 250 beaker has graduations every 25 mL. With what accuracy can you ...

maths
In a class of 80 students, 53 study Art, 60 study Biology, 36 study Art and Biology, 34 study Art and Chemistry, 6 study Biology only and 18 study Biology but not Chemistry. Illustrate the information on a Venn diagram. Determine the number of students who study (I) Arts only...

Chemistry
10. Use the accepted Ksp value of Calcium hydroxide to calculate the following: a. What is the most calcium hydroxide that can be dissolved in 1.0 Liters of de-ionized water? b. What is the most calcium hydroxide that can be dissolved in 125.0 ml of de-ionized water? c. What ...

Chemistry
A sample of 5.52 grams of NaOH is dissolved into 659 mL of aqueous 0.250 M NaOH (assume no volume change). This solution is then poured into 1.52 gallons of water. (You may assume that the two volumes can be added.) What is the concentration of NaOH in the final solution?

Chemistry
If 33.8 mL of lead(II) nitrate solution reacts with excess sodium iodide to yield 0.865g of precipitate, what is the molarity of the lead(II) ions in the original solution? im not exactly sure how to start this problem. But i went ahead and gave it a shot .865 PbI2 x 1 mol ...

Chemistry
The mass of an empty container is 91 g. The mass of the container filled with water is 111 g. What is the volume of the container? The density of water is 1 g/cm3 .Answer in units of cm3 20cm3 016 (part 2 of 5) 1.0 points The container was emptied, dried, and a piece of metal ...

Chemistry
How does the polarity of water cause its cohesive property? Describe with an example that we can actually see. I really need help with this!!! Especially on describing an example that we can actually see..... Can someone please explain this to me and give me an example?

science chemistry
balance Redox :- CuS + SO4²- = CuO+SO2

chemistry
One isotope of a nonmetallic element has mass number 16 and 7 neutrons in the nucleus. The anion derived from the isotope has 10 electrons. Write the symbol for this anion. I thought the answer was O^2- but this isnt correct

chemistry
The diameter of a neutral neon atom is about 1.4 ✕ 10^2 pm. Suppose that we could line up neon atoms side by side in contact with one another. Approximately how many neon atoms would it take to make the distance from end to end 1 cm? I did 1.4 x 10^2 pm x (1 m/10^9 pm) ...

chemistry
How many kilojoules are required to melt 15g of ice at 0 degrees C, and raise the temperature of the liquid that forms to 85 degrees C?

Chemistry help please!
Why does a clear, saturated solution of PbI2 form a yellow precipitate when a small amount of KI is added to the solution? A. KI is insoluble in PbI2. B. PbI2 is always insoluble in water. C. Adding KI is like adding I-, which drives the reaction toward the formation of I-. D...

Chemistry please help!
What happens to the following reaction at equilibrium if the pressure is decreased? 2H2(g) + O2(g) 2H2O(g) A. The equilibrium shifts left because Q > K. B. The equilibrium shifts right because Q < K. C. The equilibrium shifts left because Q < K. D. The equilibrium ...

CHEMISTRY
BLEACHING AGENT OF CHLORINE(Cl)

Chemistry
Heating 1.0 mole of ammonia and 1.0 mole of molecular nitrogen at 723k in a 10L flask,the following equilibrium is observed: N2(g)+3H2(g)=2NH3(g) when the equilibrium is reached ,0.40 moles of molecular hydrogen are present in the flask,determine Kp and Kc and equilibrium ...

Chemistry
H2S decomposes at 438k ,according to the following equilibrium: H2S(g)=H2(g)+S(s) Knowing that Kc=1.1*10-2,determine the gram amount of sulfur formed at the equilibrium coditions in a 5L flask ,where the initial concentration of H2S was 0.7M. Also,calculate Kp.

Chemistry
10g of NOBr were added to a 5L flask and the temperature was fixed to 350K. The following equilibrium is reached : NOBr(g)=NO(g)+1/2Br2(g);The pressure measured at the equilibrium was 0.63 atm.Determine Kp and Kc. I need help to solve this problem.I already done 50% but at the...

Chemistry
If you had dehydrated 1.00g of the hydrate CaCl2 ∙6H2O how many grams of anhydrous CaCl2 would you expect to be produced? Show calculations. I really am having a hard time with this question. I don't know where to start and how to perform it.

Chemistry
a. Write and balance the equation for the reaction of calcium carbonate with hydrochloric acid, then answer the following questions. b. What mass of calcium carbonate is required to neutralize 83.5mL of 6.00M HCl? does the balanced equation have any significance in this ...

Chemistry
How do i calculate these and express the answers in significant digits? 2.865 x 10^4m x 1.47 x 10^3 8.071 cm^2/ 4.216 1.142 x 10^-8 mm^2 / 8.5 x 10^-4 mm i tried the first one and got 4212. but i don't know if it's right

Chemistry
Calculate the concentration of chloride ions in the following solution. 73.28g of sodium chloride in 862. mL of solution. would it be 73.28g x 2 / 58.44g NaCl = 2.50 mol of Cl 2.50 mol Cl / .862 L = 2.91 M Cl

Chemistry
1.0 x 10^5 mL=m^3

Chemistry
Calculate the number of moles of Cl atoms in 6.28 mg CuCl2.

chemistry
suppose that you have a micro pipet which delivers 100 drops per cubic centimeter, and a solution of 5.0% by volume of oil in alcohol. if you had used 10 drops of this solution, how many cubic centimeters of pure oil would be left after evaporation of the alcohol?

Chemistry
There have been two ways on making transuranium elements: neutron bombardment and a)beta bombardment b)gamma bombardment c)positron bombardment d)photon bombardment e)heavy atom bombardment

chemistry
a graduated cylinder containing 75.0 mL of water has a mass of 149.86 g. A piece of metal is added to the cylinder and the volume of the water changes to 86.3 mL. The mass of the graduated cylinder, water and metal rises to 218.90 g.

calculus and chemistry
A container of hot liquid is placed in a freezer that is kept at a constant temperature of 10°F. The initial temperature of the liquid is 160°F. After 5 minutes, the liquid's temperature is 60°F. How much longer will it take for its temperature to decrease to 20°F? (Round ...

Chemistry
The mineral dolomite has the formula caco3.mgco3. When dolomite is heated for an extended period of time at elevated temperature it decomposed to give carbon dioxide and a mixture of calcium oxide and magnesium oxide. If a 5.424 g sample of the mineral is heated for several ...

Chemistry
KMnO4 + H2SO4 + H2S will give K2SO4 + MnSo4 + H20 + S

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