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Homework Help: Science: Chemistry

Recent Homework Questions About Chemistry

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

Chemistry 2
we make a solution of water and ethylene glycol c2h4(oh)2 which contains 24 g of the glycol for each 74 g of water. What is the boiling point of ethylene?

Chemistry
Equal volume. Of mixture of 2 solution with ph = 2 and ph = 12 find out the ph of the resultant mixture

Chemistry
Calculate the volume of 0.05 M NaOH which must be added to 100 cm3 of 0.05 M methanoic acid to obtain a buffer of pH 4.23. (Ka for methanoic acid = 1.77 x 10-4)

chemistry
Write balance half ionic equation when aluminum oxide is decomposed to aluminum and oxygen.

chemistry
A sample on analysis shows 50% cao what will be the % of calcium carbonate in it

Chemistry
A stock solution of sulfuric acid must be diluted by adding 25.0mL of 7.50M H2SO4 to enough water to make 500mL of diluted soultion. What is the concentration of the diluted solution?

Chemistry
If 8.723 grams of sodium bicarbonate are dissolved in water to produce a 250.0mL solution, what is the morality of this solution?

Chemistry
On a practice exam, we have a question that says "How many enantiomers does kendomycin have?" It says the answer is 1, but I don't understand why? (You probably have to google a picture of kendomycin!!)

Chemistry
If 8.723 grams of sodium bicarbonate are dissolved in water to produce a 250.0mL solution, what is the molarity of this solution?

chemistry
Which one of the following complex ions has an optical isomer? a. [Zn(phen)2]2+ b. [Cu(CN)4]2– c. [Co(H2O)4en]2+ d. [Zn(NH3)2en]2+ e. [Ni(en)3]2+ is the answer a) im confused as to what phen and en stand for.

Chemistry
On a practice exam, we have a question that says "How many enantiomers does kendomycin have?" It says the answer is 1, but I don't understand why?

organic chemistry
Free-radical halogenation can occur with chlorine and a source of direct UV radiation or sunlight. Chlorination of 2,4-dimethylpentane via radical halogenation leads to the formation of all three of the below products. Estimate the relative percentages of each product that ...

Chemistry
1) The letter "p" in the symbol 4p^3 indicates the ___. A) spin of an electron B) orbital shape*** C) principal energy level D) speed of an electron 2) If the spin of one electron in an orbital is clockwise, what is the spin of the other electron in that orbital? A) Zero B) ...

Chemistry
A lead fishing weight cotains 0.12 mol of lead atoms. What is its mass?

Chemistry
What would be the wavelength of a 50-gram golf ball traveling at 40 meters/second? Is this large enough to be observable?

Chemistry
CO2(g)+CaSiO3(s)+H2O(l)→SiO2(s)+Ca​(HCO3)2(aq) Balance using smallest multiples

Science (Chemistry)
"Calculate the amount of heat (kcal) released when 18.0 g (grams) of steam are condensed at 100.0 C and the resulting water is frozen and cooled to 25.0 C." The only problem that I'm having is the amount of physical and temperature changes that there are. I'm new and still ...

Science (Chemistry)
"Calculate the amount of heat (kcal) released when 18.0 g (grams) of steam are condensed at 100.0 C and the resulting water is frozen and cooled to 25.0 C." The only problem that I'm having is the amount of physical and temperature changes that there are. I'm new and still ...

chemistry
What volume of air is needed to burn an entire 60-L (approximately 16-gal) tank of gasoline? Assume that the gasoline is pure octane, C8H18. Hint: air is 20% oxygen by volume, 1 mol of a gas occupies about 25 L at room temperature, and the density of octane is 0.70 g/cm3.

chemistry
Consider the following reaction. 4Fe + 3O2 2Fe2O3 a. How many moles of O2 are required to react completely with 46.7 mg of Fe? How many grams Fe2O3, are produced from the complete reaction of 20.1 g of Fe?

Chemistry
Predict the effect of each of the following by mass of water in the hydrate and the chemical of the hydrate? a) not heating the hydrate enough b) overheating the hydrate and producing some copper (ii) oxide C) the initial hydrate appears to weigh less than it actually did, but...

Chemistry
a sample of an ionic compound is dissolved in water and the water gets colder. what is acting as the system?what is acting as the surroundings? does the heat flow from the system to the surroundings or from the surroundings to the system? is this extothermic or endothermic?...

Chemistry
a piece of metal is heated by placing it in hot oil. it is removed from the hot oil and placed into a calorimeter of cold water. the water heats up due to the transfer of heat from the metal. what happens to the temperature of the calorimeter? how is the heat that causes the ...

Chemistry
Write equations for the dissociation of the following in water. Do not include states in your answer. 1) sodium acetate (NaC2H3O2) NaC2H3O2 ---> Na+ + (C2H3O2)- 2) copper(II) perchlorate Cu(ClO4)2 ---> Cu2+ + 2(ClO4)- Enter balanced ionic and net ionic equations for ...

Chemistry
Calculate ΔHrxn for the following reaction: CaO(s)+CO2(g)→CaCO3(s) Use the following reactions and given ΔH′s. Ca(s)+CO2(g)+12O2(g)→CaCO3(s), ΔH= -812.8 kJ 2Ca(s)+O2(g)→2CaO(s), ΔH= -1269.8 kJ

chemistry
explain the meaning of this statement"specific heat capicity of alumminium is 900J/kg°C"

chemistry
Lewis sit structure of CH3OH

Chemistry
How do you do significant figures. How dobyou do dimensional analysis

Chemistry
The atomic mass of CU 63 is 62.9296 amu with a natural abudance of 0.692. The average mass of copper is 63.546amu.What is the mass of copper's other isotope?

chemistry
when 2g of a gas A is introduced into an evacuated flask kept at 25 centigrade, the pressure is found to be 1 atmosphere.if 3g of another gas is then added to the same flask, the total pressure becomes 1.5atm. assuming ideal behaviour, the ratio of their molecular weights is

chemistry
at 127 centigrade and 1 atm pressure of a gas contains 0.3mole of nitrogen molecule, 0.2 mole of oxygen molecule.the volume of the mixture is

Chemistry
24.5 g of H2SO4 (98 g/mol) is added with h20 to make up to 800 ml of a solution. If 50 ml of the H2SO4 is added with 100 ml of H20, what will be the molarity of the diluted solution? MaVa=MbVb (0.3125)(50)=(Mb)(100) Mb= 0.16 M No huh?

Chemistry
Among the following electrons, which has highest energy? a. n = 3, l = 2, m = 0, s = + 1/2 b. n = 4, l = 0. m= 0 , s = - 1/2 Ans is A... but how A? Why nOt B?

chemistry
complete the equation for the reaction of the soap with magnesium chloride

chemistry
Say some exples for true solutions.

chemistry
Which one of the following complex ions has an optical isomer? a. [Zn(phen)2]2+ b. [Cu(CN)4]2– c. [Co(H2O)4en]2+ d. [Zn(NH3)2en]2+ e. [Ni(en)3]2+ how would i go about finding this answer? i don't need the answer give would prefer steps. thanks

Chemistry
In a constant-pressure calorimeter, 65.0 mL of 0.320 M Ba(OH)2 was added to 65.0 mL of 0.640 M HCl. The reaction caused the temperature of the solution to rise from 21.98 °C to 26.34 °C. If the solution has the same density and specific heat as water (1.00 g/mL and 4.184 J/g...

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/(g·°...

Chemistry
Al3+ and HPO42

chemistry
What mass of iodine would react with 48 grams of magnesium to make magnesium iodide?

Chemistry
I have a question about solubility rules and net ionic equations so for example : CuSO4+Ba(NO3)2----->BaSO4+Cu(NO3)2 Okay so I know BaSO4 is insoluble while Cu(NO3)is solulable, that means BaSO4 will have a precipitate while Cu(NO3) doesn't. So does that mean the overall ...

Chemistry
Why does the element calcium react with water differently than magnesium, potassium and sodium, in a way that calcium looks opaque and cloudy in water and when phenlotphtahein is added it looks bright pink but how come the other elements don't look like that in water? what ...

physical chemistry
Calculate molarity of air having malar mass 28.8cotaining N2 and O2 only at 273kelvin and 1atm pressure

Chemistry
What are the names of the reactants in this equation? Mg (s) + 2HCl (aq) --> MgCl2 (aq) +H2 (g)

Chemistry
Why alkali metals known as alkali metals?

Chemistry
Complete and balance the following equation. If no reaction occurs, write noreaction . NaOH(aq)+FeBr3(aq)→

Chemistry
sorry i will rephrase the question. what is the chemistry behind these elements to give them these qualities and make them react the way they do with like water and such. 1)magnesium 2)calcium 3)potassium 4)sodium

MS. SUE HELP- Chemistry
Check answers? 1) Why did J.J. Thomson reason that electrons must be a part of the atoms of all elements? A) Cathode rays are negatively charged particles**** B) Cathode rays can be deflected by magnets C) An electron is 2000 times lighter than a hydrogen atom D) Charge-to-...

Chemistry
What is happening on a chemical basis, to make them the way they're. 1) magnesium 2)calcium 3)potassium 4)sodium

Organic Chemistry
How many constitutional isomers have the molecular formula C3H6S ?

Chemistry
H3C6H5O7(aq) + 3NaHCO3(aq)----Na3C6H5O7(aq) + 3H2O(i) + 3CO2. NaHCO3 = 2.00g H3C6H5O7 = 0.76 CO2 = 0.07g 1.Determine which reactant is the limiting reactant . describe your reasoning. 2. Calculate the theoretical yield of carbon dioxide in the plastic 3. what is the actual ...

chemistry
How many grams silver (Ag) is added to 13 grams gold to produce 85% gold (Au) alloy? Can someone please give me the derived formula to be used? I had managed to solve it though I'm not quite sure if it's correct. i got 73.67g Ag, can someone please correct me if i'm wrong. ...

chemistry
Molten Al2O3 is reduced by electrolysis at low potentials and high currents. If 1.5 x 10^4 amperes of current is passed through molten Al2O3 for 8.0 hours, what mass of Al is produced? Assume 100% current efficiency? Mdep = ([1.5 x 10^ x 28800s ]/ 96500) x (26.98/6e) = 20130g ...

Chemistry
Check answers? 1) Why did J.J. Thomson reason that electrons must be a part of the atoms of all elements? A) Cathode rays are negatively charged particles**** B) Cathode rays can be deflected by magnets C) An electron is 2000 times lighter than a hydrogen atom D) Charge-to-...

Chemistry
calculate the energy needed to warm the melted ice from 0 degrees celsius to the final temperature of the water

chemistry
A 100-watt light bulb radiates energy at a rate of 100 J/s. (The watt, a unit of power or energy over time, is defined as 1 J/s.) If all of the light emitted has a wavelength of 525 nm , how many photons are emitted per second? okay so i do: ((6.626*10^-34)(3.00*10^3))/(5.25*...

Chemistry
Calcium chloride, CaCl2, is used in “hot packs”. When the solid is mixed with water, the products are favored. Based on this information, which of the following is true for the values of ΔH and ΔS for the dissolving process? CaCl2 (s) → Ca2+ (aq) + 2 Cl&#...

Chemistry
Ammonium nitrate, NH4NO3, is used in “cold packs”. Which statement best describes why the products are favored, when the solid is mixed with water? NH4NO3(s) → NH4+ (aq) + NO3- (aq) A) Heat is transferred to the surroundings to lower the temperature and the entropy ...

Science,chemistry
How do I write a balanced half ionic equation of aluminium oxide at the cathode?

AP Chemistry
Sodium can be extracted by heating naturally occurring salt until it is molten. An electrochemical process is then used to extract the sodium. Cl2 is produced at the anode, and Na is collected at the cathode. 1. Write the half-reactions that occur at the anode and the cathode...

Chemistry
When excited electron of phosphorus goes in d orbital from p orbital then particularly in which orbital of d (5 coz there are 5 suborbitals in d) that electron goes? And why?

Chemistry
Cobalt metal is added to steel to improve its resistance to corrosion.Calculate no. of moles in a cobalt contain 5×10^20

Chemistry
what are dipoles?

Chemistry
Is the atomic mass or atomic weight on the periodic table written in grams.

Chemistry
To what volume should 10L of 0.5M CH3COOH (Ka = 1.8×10–5) be diluted in order to double the OH– concentration?

Chemistry
Consider the following reactants. Which produces a gas? 1. NH4Cl(aq) + AgNO3(aq) → 2. Na2CO3(aq) + BaCl2(aq) → 3. Na2S(aq) + HCl(aq) → 4. All of these would produce a gas.

Chemistry
Does helium have an ionic radius? I searched and looked in an old Chem book, and come up empty. Hydrogen is not listed either. Is there a specific reason for this? Thank you.

Chemistry
What is the molar volume of pure water at 22 degrees Celsius?

Chemistry
Identify the precipitate(s) of the reaction that occurs when a silver nitrate solution is mixed with a sodium chloride solution. Check all that apply. silver nitrate sodium chloride sodium nitrate silver chloride

CHEMISTRY PLS HELP
If a sample of red blood cells at an osmotic pressure of 7.70 atm is placed in a solution that contains 0.050M calcium chloride (CaCl2) at 25°C, what is the freezing point of this solution if the density of the solution is 1.50 g/mL

Chemistry
If 0.0365 mol of CaCl2 is dissolved in water to make a 0.640 M solution, what is the volume of the solution?

Chemistry
1) 2 kg of solid copper is at its melting point. How much energy does it take to melt all the copper? Heat of fusion: 134 J/g Heat of Vaporization 5060 J/g q= mHf I know the equation but I do not understand know if this is correct. 2kg= 2000 grams q=(2000g) (134J/g) q=(2000) (...

Chemistry
Calculate normality of 27% H2SO4

Chemistry
In the titration of a solution of a weak acid HA with NaOH the pH is 5.0 after 10ml of NaOH solution has been added and 5.6 after 20ml of the NaOH solution has been added. Find the PKa of HA? Pls give some hints to solve this question...

chemistry
What is the composition of a methanol () – propanol () solution that has a vapor pressure of 121 torr at 40°C? At 40°C, the vapor pressures of pure methanol and pure propanol are 303 and 44.6 torr, respectively. Assume the solution is ideal. Mole fraction of methanol = ...

chemistry
Pentane (C5H12) and hexane (C6H14) form an ideal solution. At 25oC the vapor pressures of pentane and hexane are 511 and 150 torr, respectively. A solution is prepared by mixing 25 mL pentane (density, 0.63 g/mL) with 45 mL hexane (density, 0.66 g/mL). What is the vapor ...

chemistry
A solution is made by dissolving 22.9 g urea (), a nonelectrolyte, in 302 g water. (The vapor pressure of pure water is 23.8 torr at 25°C and 71.9 torr at 45°C.) Calculate the vapor pressure of this solution at 25°C. Vapor pressure = torr Calculate the vapor pressure of ...

chemistry
The normal boiling point of methanol is 64.7oC. A solution containing a nonvolatile solute dissolved in methanol has a vapor pressure of 670.0 torr at 64.7oC. What is the mole fraction of methanol in this solution?

chemistry
Glycerin, C3H8O3, is a nonvolatile liquid. What is the vapor pressure of a solution made by adding 159 g glycerin to 338 mL H2O at 39.8oC? The vapor pressure of pure water at 39.8oC is 54.74 torr and its density is 0.992 g/cm3.

chemistry
Calculate the solubility of in water at a partial pressure of of 140. torr at 25°C. The Henry's law constant for is for Henry's law in the form C = kP, where C is the gas concentration (mol/L).

chemistry
What mass of glycerin (), a nonelectrolyte, must be dissolved in 200.0 g water to give a solution with a freezing point of –0.900°C?

chemistry
The weight of a china dish with a saturated solution of sodium nitrate at 40°C is 80 g. After evaporating the whole solution the dish's weight along with the crystals is 40 g and solubility of NaNO3 at 40°C is 20 g. What is the weight of empty china dish ?

Chemistry
15.00g of ammonium nitrate decomposes into an expandable container acoording to the following equation. 2NH4NO3 ==> 2N2 g + 4H2O g + O2 g which has the highest partial pressure a. N2 b. H2O c. O2 i am not sure how to approach this problem. is there a simple way to solve ...

Chemistry
Classify the following reactions as precipitation reactions, oxidation-reduction reactions, or acid-base reactions. 1)2NaCl(aq)+K2H2Sb2O7(aq)==Na2H2SbO7(s)+​2KCl(aq) 2)(CH3COO)2Cu(aq)+(NH4)2C2O4(aq)==CuC2O4​(s)+2CH3COONH4(aq) 3)4Al(s)+3O2(g)==2Al2O3(s) 4)2Zn(s)+O2(...

Chemistry
When methane are burned in a bomb calorimeter the temperature rises from 21.00℃ to 25.18℃. The heat capacity of methane is 3.754x10^3 J/℃. The amount of heat, q (in kJ) absorbed by the calorimeter apparatus is: Correct Answer: 18.68 kJ My Work and my answer: ...

Chemistry
B2O3(s) + 3C(s) + 3Cl2 (g) ---> 2 BCl3(g) + 3CO(g) How many moles of chlorine are used up in a reaction that produced 0.35 kg of BCl3 I do not understand please help

Chemistry
2NO(g) + O2 (g) --> 2NO2 How many grams of NO are required to react fully with 5.00 mol of O2? I do not understand any of this please help

chemistry
WHAT does it mean for a phase of matter to have a definite shape and volume

Chemistry
The following replicate values were reported for the concentration of magnesium chloride, MgCl2, in mol/L. What value should be reported as the mean concentration of the chloride ion, Cl-, converted to ppm? (You may use the simplified definition of ppm.) 0.00141, 0.00138, 0....

chemistry
A metal bar having a mass of 212 g is heated to 125.0 C and then dropped into 375 g of water at 24.0 C. After a while the temp of the water and the metal is 34.2 C. If the specific heat of the metal is 0.831 J/g C, how much heat did the metal lose? How much heat did the water ...

Chemistry
How many grams of solid KOH must be added to 100ml of a buffer solution which is 0.1M each with respect to the weak acid HA and its potassium salt KA in order to make the pH of the solution 6.0?

chemistry
Write the balanced chemical equation for the oxidation of catechol to quinone.

Chemistry
Identify the oxidation-reduction reactions among the following: 1. Zn(s) + Cu2+(aq) → Zn2+(aq) + Cu(s) 2. 2Na(s) + Cl2(aq) → 2NaCl(s) 3. 2Mg(s) + O2(g) → 2MgO Identify the oxidation-reduction reactions among the following: 1 and 2 only 2 and 3 only 1 and 3 ...

Chemistry
1.025g of an impure sample of a weak acid HX(mol mass = 82) is dissolved in 60ml of water and titrated with 0.25M NaOH. When half of the acid was neutralized the pH was found to be 5.0 and at the equivalence point the pH is 9.0. Find the % purity of this sample of HX Pls help...

Chemistry
0.299 g of NH4Cl is dissolved in 50.0 ml then titrated against 0.205 M NaOH. Calculate the pH at the equivalent point

Chemistry
Base = NaOH, 0.084 M drips 2ml at a time Acid = Phenol, KA=1.3*10^-10 You have 28.0 ml in flask, and it is 0.06 M How would you find the molarity and moles of OC6H5-1

Chemistry
Calculate the value of Z and its absolute standard deviation. All standard deviations shown are absolute. Show your work and report the standard deviation in the result with two significant digits (to confirm the correct result). Z = (1.18+/-0.07)x((2.21+/-0.05)^3)

Chemistry
What two facts did Newton need to be able to calculate the acceleration of the Moon?

Science (Chemistry) (Measurement Uncertainty)
Three students are asked to determine the mass of a coon. They each measure different values for the mass of the coin using a balance. Student A recorded a mass of 63.08g, student B recorded a mass of 63.022g and student C recorded a mass of 63.0328g. If the balance is ...

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