Thursday
December 8, 2016

Homework Help: Science: Chemistry

Recent Homework Questions About Chemistry

Chemistry
1. Suppose that 10.2 mL of 0.0512 M NaOH were required to titrate a sample of unkown acid. How many moles of NaOH were used?
Monday, October 17, 2016 by Raeann

Chemistry
Why was etching needed to bring out the grain boundaries? My answer: Is it for the light to bounce back?
Monday, October 17, 2016 by Chemistry

Chemistry
What mass of calcium citrate, Ca3(C6 H5 O7)2, would a tablet manufacturer need to use to provide the same amount of Ca that you found in your tablet? (show calculations) The mass of Calcium for the experiment was .7374g We assumed that any solid that formed when Na2CO3 was ...
Monday, October 17, 2016 by Chris

Chemistry Plz Help!
How to calculate dimensional analysis using the density and molarity to calculate the percent (w/w)???
Monday, October 17, 2016 by Barbie

Chemistry
0.5g of MG ribbon is reacted with 100ml of 1M HCL. The initial temperature of HCL is 20.4 degrees celsius. After the reaction the highest recorded temperature is 40.7 degrees celsius. Calculate the molar enthalpy of MG. I tried to find mol from HCl and then use nH=mcdeltat. ...
Monday, October 17, 2016 by Jacob

Chemistry
The molar enthalpy of combustion of demand is -6.78KJ/mol.What mass of decane would have to be burned in order to raise the temperature of 500ml of water from 20 degrees Celsius to 55 degrees celsius. I tried using ndeltaH=mcdeltat. But it didn't work. Please help
Monday, October 17, 2016 by Kelvin

Chemistry
1) How does the atomic radius change from left to right across a period in the periodic table? A) It tends to decrease*** B)It tends to increase C) It first increases, then decreases D) It first decreases, then increases 2) What is the charge of a cation? A) A positive charge...
Monday, October 17, 2016 by Mary

Chemistry
Calculations involving a limiting reactant Now consider a situation in which 20.0 g of P4 is added to 54.0 g of Cl2, and a chemical reaction occurs. To identify the limiting reactant, you will need to perform two separate calculations: 1) Calculate the number of moles of PCl5...
Monday, October 17, 2016 by Beth

Organic Chemistry
Butanamide (Amide) vs Aminobutane (Amine) Which compound do you think has the higher melting point? Explain your reasoning.
Monday, October 17, 2016 by matt

Science (Chemistry) Ratio of mole
You measured out 0.101g of Mg. You heat the sample and measure out 0.234 of the magnesium oxide compound. Given your data, what us the empirical formula for the Mg(x)O(y)? x and y are ratio x:y If I'm doing this correctly, I divided 0.101g of Mg/24.31g of Mg = .00415 mol ...
Monday, October 17, 2016 by Ray

chemistry
Calculate the mass of pure NaCl that will yield enough HCl gas to neutralize 25cm3 of 0•5 of KCO3 solution
Monday, October 17, 2016 by Ozioma

chemistry
5. One hundred milligram of caffeine is dissolved in 50 mL of water. a. How many mg of caffeine will remain in the water if you extract with 20 mL of methylene chloride? Show your calculations (KD = 4).b. How many mg of caffeine will remain in the water if you extract two ...
Monday, October 17, 2016 by reem

chemistry
The 17.35 g of NaCl sample was dissolv ed in an unknown amount of water. All we know is that prepared solution has 22.5% of NaCl . The mass of water is _____ g.
Monday, October 17, 2016 by shawna

Chemistry
A sample of cobalt, A, with a mass of 5g is initially at 25 degrees Celsius. When this sample gains 6.70J of heat, the temperature rises to 27.9 degrees Celsius. Another sample of cobalt B with a mass of 7 g is initially at 25 degrees Celsius. If sample B gains 5 J of heat, ...
Monday, October 17, 2016 by Matthew

Chemistry
A solution of potassium permanganate (KMnO4) was standardised by titrating with 0.1908 g of Na2C2O4 dissolved in 50 cm3 of acidified water. The endpoint was reached after 24.50 cm3 of solution had been added. Calculate the molar concentration of KMnO4 in the solution.
Monday, October 17, 2016 by Anonymous

Chemistry
A solution of potassium permanganate (KMnO4) was standardised by titrating with 0.1908 g of Na2C2O4 dissolved in 50 cm3 of acidified water. The endpoint was reached after 24.50 cm3 of solution had been added. Calculate the molar concentration of KMnO4 in the solution.
Monday, October 17, 2016 by Anonymous

Chemistry
Calculate the molarity of Fe(NO3)3 in Solution A. Solution A: Mass of Fe(NO3)3 solid: 1.21g & Vol of Solution: 100mL In a previous ? Using the mass I weighed 404.0g/mol to calculate moles of Fe(NO3)3 in solid hydrate----I got 0.00300 mol Fe(NO3)3)
Monday, October 17, 2016 by Rosie

Inorganic Chemistry
A 1.577 M solution of AgNO3 has a density of 1.220 gram per centimeter cube. What is the molality of the solution?
Sunday, October 16, 2016 by Cris

Inorganic Chemistry
What is the mole fraction of solute in a 1.00 molal solution in which toluene (C7C8) is the solvent.
Sunday, October 16, 2016 by Cris

Inorganic Chemistry
Methyl Alcohol (CH3OH) and ethyl alcohol (C2H5OH) form ideal solutions at 50°C, the vapor pressure of pure methyl alcohol is 0.529 atm, and the vapor pressure of pure ethyl alcohol is 0.292 atm. What is the vapor pressure at 50°C of a solution containing 24.00 g of ...
Sunday, October 16, 2016 by Cris

Inorganic Chemistry
what is the molarity of concentrated hydrogen fluoride if the solution is 48% by mass and has a density of 1.17 gram per milliliter.
Sunday, October 16, 2016 by Cris

Chemistry
A hypothetical pure element consists entirely of two isotopes. The natural percent abundance of the isotope with mass 25.5 u is 78.8 percent. The other isotope has mass 29.5 u. Calculate the atomic weight of the naturally occurring element.
Sunday, October 16, 2016 by Amanda

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.i.how many students passed biology ii.how many students passed chemistry iii.how many students passed only ...
Sunday, October 16, 2016 by Obert

chemistry help
Chlorine has two Isotopes with mass number of 35&37.if the relative atomic mass is 35.5, find the percent abudance of Cl-35(isotope with mass number 35)
Sunday, October 16, 2016 by Anonymous

Chemistry
what is the energy if a photon of red light that has a wavelength of 8.90x10^-7
Sunday, October 16, 2016 by Anonymous

Chemistry
What is the total no. Of atoms present in 25.0 mg of camphor
Sunday, October 16, 2016 by sneha

chemistry
No. Of atoms in 12g of Mg is equal to
Sunday, October 16, 2016 by sneha

Chemistry a level
A solution of potassium permanganate (KMnO4) was standardised by titrating with 0.20 g of Na2C2O4 dissolved in 50 cm3 of acidified water. The endpoint was reached after 23.10 cm3 of solution had been added. Calculate the molar concentration of KMnO4 in the solution.
Sunday, October 16, 2016 by Rob

chemistry
what is the type of catalyst that corresponds the use of the platinum wire
Sunday, October 16, 2016 by vicky

Chemistry
What is the maximum mass, in grams, of NH3 that can be produced by the reaction of 1.0 g of N2 and 1.0 g of H2 using the reaction below? N2+H2→NH3 (not balanced) What is the maximum mass, in grams, of that can be produced by the reaction of 1.0 g of and 1.0 g of using ...
Sunday, October 16, 2016 by Beth

chemistry
Zinc react with diluted sulfuric acid to give hydrogen but silver doesn't explain?
Sunday, October 16, 2016 by Anonymous

Chemistry
A sample of acetone having a mass of 1.920 g undergoes complete combustion in an insulated calorimeter holding 400 mL of water. It is determined that the water and calorimeter together absorb 58.829 kJ of heat energy from this combustion. Based on this information, what is the...
Saturday, October 15, 2016 by lomonoyan

Chemistry
A reaction in a calorimeter containing 80.0 g of water at 20 degrees Celsius causes the temperature to fall by 1.5 degrees. what is the thermal energy of the water? I got 6.2 J or 6192.32 kJ but they say 5.02 x 10^4 kJ idk what I am doing wrong
Saturday, October 15, 2016 by lomonoyan

chemistry
Back to the atomic emmission spectrum and the atomic theory. in the 1900s, scientists observed that when a gaseous element, such as hydrogen was subjected to an electric discarge that the atoms emitted electromagnetic radiation. The light emmitted could be separated into ...
Saturday, October 15, 2016 by lulu

chemistry
Explain how understanding of the atomic emmission spectrum led to developement of the atomic theory. The emmissions spectrum for each element is unique. You can identify an eleement by its spectrum. The atomic theory states that all atoms of a given element are identical. The ...
Saturday, October 15, 2016 by lulu

Chemistry
Rain drops fall on a tile surface at a density of 4380 drops/ft^2. There are 15 tiles/ft^2. How many drops fall on each tile? Answer in units of drops/tiles.
Saturday, October 15, 2016 by Anna

Chemistry
Describe in detail how you would make 1.25 of 0.125 M potassium permanganate solution. I think you have to set up an equation for molarity but I'm not sure. Please help.
Saturday, October 15, 2016 by Johnathan

CHEMISTRY
The specific heat of copper is 0.386 J/gºC. A 20.0 g sample of copper is heated from 25.0 ºC to 35.0 ºC. How much heat did the copper absorb?
Saturday, October 15, 2016 by TEE

chemistry
Consider the reaction below. C3H8 + 5 O2  3 CO2 + 4 H2O How many litres of CO2 will be produced when 10.0 L of O2 are completely reacted with C3H8? Assume that the volumes of the reagents and products are measured at constant pressure and temperature.
Saturday, October 15, 2016 by tia

chemistry
75.0 mL of a 1.50 M solution is diluted to a total volume of 278 mL. A 139-mL portion of that solution is diluted by adding 139 mL of water. What is the final concentration? Assume the volumes are additive.
Friday, October 14, 2016 by tia

Science-chemistry
How do I calculate the amount of heat will be required to make 100.0kg of a compound, the molar enthalpy is -63kj/mol for the same compound
Friday, October 14, 2016 by Sophia

science (chemistry)
The % (by weight) of methanol in a mixturevof methanol and ethanol is50%.Therefore,the mole fraction of methanol in the mixture is
Friday, October 14, 2016 by muskan

Chemistry
Two substances, gold and granite, initially at different temperatures, come into contact and reach thermal equilibrium. The mass of gold is 20.2 g and its initial temperature is 58.2 ∘C. The mass of granite is 29.1 g and its initial temperature is 20.1 ∘C. What is ...
Friday, October 14, 2016 by Diana

chemistry
Element x Isotope 55x 60% Isotope 56x 30% Isotope. 57x 10% 55× 60 =3300 56×30=1650 57× 10= 570 Add them up5520 divide by 100 the atomic weight of x is 55.2 Pls check if this is correct , answer and method
Friday, October 14, 2016 by lulu

general chemistry
2C6H6(l)+15O2(g)-> 12CO2(g)+6H20(l)+6542 kj If 6.200 g of C6H6 is burned and the heat produced from the burning is added to 5691 g of water at 21 °C, what is the final temperature of the water?
Friday, October 14, 2016 by fer

Chemistry
In order to determine the concentration of a solution of Carbonic Acid (H2CO3), a sample was placed in a buret and titrated with 0.1132 M Sodium hydroxide. For the carbonic acid, the initial reading was 11.0ml and final reading was 31.0 ml. For sodium Hydroxide, the initial ...
Friday, October 14, 2016 by Andrew

chemistry 11
i did a lab on separation of salt and sand. the initial mass that my teacher gave me was the stock mixture that was: salt= 54.79g; sand= 97.90g. after the experiment my mass were as follow: salt= 1.35g; sand= 3.17g. question #1 was asking about the % composition of the mixture...
Friday, October 14, 2016 by Annon

chemistry 11
i did a lab on separation of salt and sand. the initial mass that my teacher gave me was the stock mixture that was: salt= 54.79g; sand= 97.90g. after the experiment my mass were as follow: salt= 1.35g; sand= 3.17g. question #1 was asking about the % composition of the mixture...
Thursday, October 13, 2016 by annon

chemistry
After the suction filtration, the filtrate in the suction flask contains (among other things) some dissolved product, which had failed to crystallize. Could you process this filtrate to obtain a sample of the product? Explain. Would the second crop of crystals be as pure as ...
Thursday, October 13, 2016 by Anonymous

chemistry
draw the skeletal structure line-angle (line-bond) mode of 2-isopropyltoluene. Identify the number of hydrogen atoms bound to each carbon in the structure.
Thursday, October 13, 2016 by sarah

Chemistry
If a reaction was started with 3 mL of TEOS in H2O and yielded 0.3275 grams of SiO2. what is the percent recovery of SiO2?
Thursday, October 13, 2016 by Guy

college chemistry
how many L @STP if oxygen are needed to produce 45.0 grams of nitric oxide according to the following balanced chemical equation? 4NH3 + 5O2=4NO + 6H2O
Thursday, October 13, 2016 by Lilly

Chemistry
Assume that the reaction was limited by the surface area of the nails, making Fe the limiting reactant. Based on the decrease in the mass of nails, calculate theoretical yield of copper. 2Fe+3CuCl2--->2FeCl2+3Cu
Thursday, October 13, 2016 by Maddy

Chemistry
Write a balanced equation assuming iron oxidizes to iron (II). I used CuCl_2 in the experiment.
Thursday, October 13, 2016 by Barbie

chemistry,
Could you pls check back a few questions. The first 1 or 2 digits in each nmber is the family number, so the numbers do not go on a consistant trend. Thank you
Thursday, October 13, 2016 by lulu

Chemistry
What is the advantages and disadvantages of using sodium carbonate to soften water?
Thursday, October 13, 2016 by Edison

chemistry
calculate the normality of 4g of sodium hydroxide in 100ml of solution
Thursday, October 13, 2016 by arul raj

chemistry
Analysis of a compound yields the following percentage composition.65.03 of Ag;15.68Cr;19.29 O. the simplest formula of the compound is?
Thursday, October 13, 2016 by Sai

chemistry
The percentage of nitrogen in magnesium nitride is.?
Thursday, October 13, 2016 by Sai

chemistry
For the elements in row 2 of the PT discover the relationship between ionization and the family number of the element Element. Family. Ionization Ener Lithium. 1 13.6 beryllium. 2. 9.3 boron. 13. 8.3 carbon. 1 4. 11.27 nitrogen. 15 14.53 oxygen. 16. 13.62 fluorine. 17. 17.42 ...
Thursday, October 13, 2016 by lulu

chemistry
When calling the families on the periodic chart by the top or first name in the column, where hydrogen is a non metal, and in family 13, where boron is a metaloid , is it correct to call those families the hydrogen or lithium family or/ and the boron family and for family 14, ...
Wednesday, October 12, 2016 by lulu

Chemistry
How many moles of ions are in 1.0 mol NH4Cl?
Wednesday, October 12, 2016 by Isaiah

Chemistry
Net Ionic equation for 1. Iron(II) Iodide and Magnesium Acetate 2. Ammonium Phosphate and Cobalt(III) Chloride 3. Sodium Acetate and Potassium Chloride These are the only ones I have left on my HW and I can't seem to figure them out would appreciate some help.
Wednesday, October 12, 2016 by Jake

Chemistry
What is the Net Ionic Equation for Nitric Acid and Potassium Carbonate?
Wednesday, October 12, 2016 by Alan

Chemistry
Lactose Aspartame Sucrose Sucralose Saccharin which ones of these are polar, which are non-polar? and what is the structures of them? like their O-H bonds? i found answers to other sugars like glucose and fructose but need help for these
Wednesday, October 12, 2016 by Holfbrincl

Chemistry
What is the concentration in each of the following solutions? A) 240 mL of 0.200 M KNO3 is added to 160 mL of water. B) 2.25g of NaCl is dissolved in 250 ml of water.
Wednesday, October 12, 2016 by Alan

Chemistry
The quantity of Cl- in a water supply is determined by titrating the sample with Ag+. What mass of chloride ion is present in a 10,0g sample of the water if 20.2 ml of 0.100 M Ag+ is required to react with all the chloride in the sample?
Wednesday, October 12, 2016 by Alan

Chemistry
In order to determine the concentration of a solution of Carbonic Acid (H2CO3), a sample was placed in a buret and titrated with 0.1132 M Sodium hydroxide. For the carbonic acid, the initial reading was 11.0ml and final reading was 31.0 ml. For sodium Hydroxide, the initial ...
Wednesday, October 12, 2016 by Brad

Chemistry
A hot lump of 25.6 g of aluminum at an initial temperature of 57.4 °C is placed in 50.0 mL of H2O initially at 25.0 °C and allowed to reach thermal equilibrium. What is the final temperature of the aluminum and water given that the specific heat of aluminum is 0.903 J...
Wednesday, October 12, 2016 by Joseoh

Chemistry
Based on the standard reduction potentials given below, which species is most likely to be oxidized? Ag+ + e- → Ag, Eo= 0.80 V Cu2+ + 2e- → Cu, Eo= 0.34 V Zn2+ + 2e- → Zn, Eo= -0.76 V Cd2+ + 2e- → Cd, Eo= -0.40 V I thought the answer would be Zn2+ that...
Wednesday, October 12, 2016 by James

Chemistry
I need to prepare 500 ml of a 37% w/w solution of sulfuric acid using 96% sulfuric acid in deionized water. I have been shown a bunch of different ways and they all give a different answer and I'm getting frustrated
Wednesday, October 12, 2016 by Pam

Chemistry
Consider a 0.15m calcium chloride aqueous solution a) determine the molarity of all solution. Assume that calcium chloride completely ionizes when dissolved in water. All solutes means all cations and anions. b)
Wednesday, October 12, 2016 by Zai to DrBodd22

chemistry
0.5mols of a mono alkanoicacid weighs 44 grams, determine the molecular formula and name the acid. (show the workings)
Wednesday, October 12, 2016 by EMMANUEL

Chemistry
What are the elements in Group A1 on the periodic table? alkali metals alkali earth metals inner transition metals ** halogens
Wednesday, October 12, 2016 by Selena

Chemistry
How many isomers are there in the following: 1. C2H4O (I was able to draw three.. Two involving a double bond and one involving a ring.) 2. C3H8O (I can only draw one..) 3. C2H4Cl (3 isomers?)
Wednesday, October 12, 2016 by Anonymous

Chemistry
Find dissociation constant of e thanoic acid having concentration 0.2M and degree of dissociation 50%
Wednesday, October 12, 2016 by Anu

chemistry
what happens to the mass of copper when over heated and forms copper(ii) oxide
Wednesday, October 12, 2016 by Khumo

Chemistry
Why sulphur dioxide is not directly dissolve in water?
Wednesday, October 12, 2016 by Tamaq

Chemistry
Why gay lussac's law applicable only for gases and not for solid and liquid??????????!
Wednesday, October 12, 2016 by Tamaq

Chemistry
1. A 0.70 g mixture of Cu and CuO was treated with hydrogen at elevated temperature. CuO was reduced to Cu and water was formed. (a) Write a balanced equation for the reaction. (2 marks)
Wednesday, October 12, 2016 by Lightningtx

algebra homework help
student missed 11 problems on a Chemistry test and received a grade of 65%. If all the problems were of equal value, how many problems were on the test? Round off your answer to the nearest integer. X= # of problems 11= # of missed problems 65% of correct problems 35% of ...
Wednesday, October 12, 2016 by jennifer

algebra
A student missed 11 problems on a Chemistry test and received a grade of 65%. If all the problems were of equal value, how many problems were on the test? Round off your answer to the nearest integer. X= # of problems 11= 3 of missed problems 65% of correct problems 35% of ...
Wednesday, October 12, 2016 by jennifer

Chemistry
How many isomers are there in the following: 1. C2H4O (I was able to draw three.. Two involving a double bond and one involving a ring.) 2. C3H8O (I can only draw one..) 3. C2H4Cl (3 isomers?)
Wednesday, October 12, 2016 by Anonymous

algebra homework help
A student missed 8 problems on a Chemistry test and received a grade of 47%. If all the problems were of equal value, how many problems were on the test? Round off your answer to the nearest integer. My answer is 15 question were on the test is this correct
Wednesday, October 12, 2016 by jennifer

Chemistry
Is carbon dioxide a chemical reaction? Just carbon dioxide itself... (like from fossil fuels, cars, etc.)
Tuesday, October 11, 2016 by Fading

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 electrons thus making it electrophilic. Is this correct?
Tuesday, October 11, 2016 by Anonymous

Chemistry (chromatography)
I had a chromatography experiment for chemistry and here is one of the questions: Did the compounds travel farther in the water or the isopropyl alcohol (rubbing alcohol)? Explain why you think that this is the case. Now, the compounds traveled the farthest in the water but I ...
Tuesday, October 11, 2016 by Fading

Math/Chemistry
Your friend eats 50.0g tuna steak. You find out that the tuna is 0.001% (by mass) mercury. The lethal dose of mercury is 5.5x10^-3 mg of mercury. Should you take your friend to the hospital?
Tuesday, October 11, 2016 by Ray

Chemistry
If you had not quite driven off all the water from the hydrate by the end of the excitement , there may still be water in the crucible at the final weighing , causing the final weight to be higher than expected . Would this cause your calculated waters of hydration /...
Tuesday, October 11, 2016 by Yveline

chemistry
why does line separating solids and liquids have a negative slope for water, while most compounds have a phase diagram with a positive slope?
Tuesday, October 11, 2016 by Anonymous

Chemistry
How would you make .25 Liters of a .1 M MgCl2 solution?
Tuesday, October 11, 2016 by Mayson

Chemistry
After mixing 1 g of 60% ee (+)-Kendomycin with 2 g of 80% ee (+)-Kendomycin, what is the ee of the final mixture? I know the answer is 73% ee, but I don't understand how to get to that answer!
Tuesday, October 11, 2016 by Christina

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?
Tuesday, October 11, 2016 by Nevaeh

Chemistry
25cm3 Of 3g Of Hydrated Sodium Trioxocarbonate (iv) Solution (NaCO3XH2O)per 250cm3 Was Neutralized By 13.20cm3 Of 0.16m Hydrochloric Acid Solution. 1) Write The Equation For The Reaction. 2) Calculate The Conc Of The Base In Mol/dm3. 3) Calculate The Molar Mass Of The Base. 4...
Tuesday, October 11, 2016 by Loveth

Chemistry
25cm3 Of 3g Of Hydrated Sodium Trioxocarbonate(iv) Solution (NaCO3XH2O)Per 250cm3 Was Neutralized By 13.20cm3 Of 0.16m Hydrochloric Acid Solution. Write The Equation For The Reaction. Calculate The Conc Of Base In Mol/dm3. Calculate The Molar Mass Of The Base. The Value Of X. ...
Tuesday, October 11, 2016 by Loveth

Chemistry
Please Write Out The Equation Of This Reation NaCO3XH2O
Tuesday, October 11, 2016 by Loveth

Chemistry
A calcium iodide solution is made by mixing 0.520g of calcium iodide with 12.0ml of water. 1) Determine the moles of calcium iodide used to make the solution 2) Determine the mass of solvent used to make the solution. Assume that the density of water is 1.000g/ml. 3) Determine...
Tuesday, October 11, 2016 by Faith 1

college chemistry
Predict two new ionic compounds that may form after you mix these sodium phosphate and calcium nitrate solutions. Write a balanced equation to show which ions would collide and what compound will form.
Tuesday, October 11, 2016 by lesley

Chemistry
If a solution containing 107.68 g of mercury(II) perchlorate is allowed to react completely with a solution containing 17.796 g of sodium sulfide, how many grams of solid precipitate will be formed?
Tuesday, October 11, 2016 by Julia

Chemistry
Find the ratio of the pH of solution (I) containing 1 mol of CH3COONa and 1 mol of HCl in 1L and solution (II) containing 1 mol of CH3COONa and 1 mol of CH3COOH in 1L
Tuesday, October 11, 2016 by Sandu

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Homework Help: Science