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Homework Help: Science: Chemistry

Recent Homework Questions About Chemistry

Chemistry
Calculate the number of moles of ZnCl, in 100mL of 3.00M solution.

chemistry
how many grams of NaCl required to prepare in 2500 ppm(w/v) NaCl 250 mL solution

chemistry
how to make 400 ml of 5% w/w h2so4

Chemistry
A metal, M, of atomic weight 96 u reacts with fluorine to form a salt that can be represented as MFx. In order to determine x and therefore the formula of the salt, a boiling point elevation experiment is performed. A 10.9 g sample of the salt is dissolved in 100.0 g of water...

Chemistry
Urea, which has the chemical formula (NH2)2CO, is a fertilizer that can be prepared by reacting ammonia (NH3) with carbon dioxide (CO2). Given the following chemical equation, what is the theoretical yield of urea (in grams) if 4.16 mol ammonia is the limiting reactant? 2 NH3(...

Chemistry
what volume of .422 M NaOH must be added to .500L of .300 M acetic acid to raise its ph to 4.00 i know you have to use the henderson hasselbalch equation but im not sure which values i would use for the concentration portion of the equation. would i have to change the ...

chemistry
What is the temperature of a gas that has a volume of 555ml and 43.5 atm that was initially at 20 degrees, 885 ml and 2.9 atm

Chemistry
Calculate the new volume of 23.5 mL of N2 gas initially at 220k Pa and 98.7 degrees Celsius when converted to STP

Chemistry
A 25-mL sample of 0.160M solution of NaOH is titrated with 17 mL of an unknown solution of H2SO4 What is the morality of the sulfuric acid solution.

chemistry
You measure out 3.00 mL of 0.100 M Co(NO3)2, place it in a test tube and add 7.00 mL of water. What is the concentration of the diluted solution in the test tube?

chemistry
In an experiment designed to determine the concentration of Cu+2 ions in an unknown solution, you need to prepare 100 mL of 0.10 M CuSO4 as your stock solution. How many grams of CuSO4(s) should you use?

Chemistry
At what temperature will 0.0100 mole of argon gas have a volume of 275 mL at 100.0 kPa?

CHEMISTRY
*Consider a 0.15 m strontium chloride aqueous solution. a. Determine the molality (in m) of all solutes in the solution. Assume that strontium chloride completely ionizes when dissolved in water. All solutes means all cations and anions. The molality that you determine here is...

chemistry
For the reaction 2Na(s)+Cl2(g)→2NaCl(s)2Na(s)+Cl2(g)→​2NaCl(s), how many grams of NaCl could be produced from 20 L of Cl2Cl2 (at STP)?

Chemistry
Is is possible to get 100% on a percent yield? Now, For Cup A I had : Mass of cup water & stirrer: 67.51 mass of sodium bicarbonate: 1.00g mass of citric acid: .76g total mass of all: 69.27g mass of cup, solution, stir after reaction: 68.75g difference (CO2 mass) = 0.52 My ...

chemistry
3.05 g hydrated copper sulfate produces 1.94 g of anhydrous salt.Assuming complete removal of all water of crystallisation,determine tha formula of hydrated copper sulfate.

chemistry help ?!
Which of the following is an exothermic reaction? sugar dissolving in water <<my choice an explosion tea dissolving in water the cooling of an ice pack

Chemistry
What is the volume of a 5.2 molarity solution made with 115g of LiF? I've only learned in class how to go from volume to molarity. How do you do this one?

Chemistry
Nickel (Ni) is an element found in Group 10 of the periodic table of elements (see periodic table at the top of this quiz). Based on its location in the periodic table, which of these is a property of nickel? A Low density B Strong semi conductor C Highly reactive with other ...

Chemistry
Calculate the number of H Atoms present in 0.125 g CH3OH

Chemistry
Calculate the mass in grams of 2.5*10^20 NO molecules

Chemistry
How many germanium atoms are present in 0.155g of the metal?

Chemistry
Suppose a student diluted and titrated a bleach unknown exactly as described in the experimental procedure, except only a single titration was performed which required 16.22 mL of 0.100 M Na2S2O3. The density of the original, undiluted bleach unknown was g/mL. If the number of...

Chemistry
Suppose a student diluted and titrated a bleach unknown exactly as described in the experimental procedure, except only a single titration was performed which required 16.22 mL of 0.100 M Na2S2O3. The density of the original, undiluted bleach unknown was g/mL. If the number of...

Chemistry
The volume of 10 ml of H2SO4 solution was diluted 250 ml with distilled water. This resulting solution, 25 ml were neutralized by 10 ml of 0.1 mol/L solution of NaOH. calculate the Molarity of sulfuric acid.

Chemistry
When 0.010 moles of Zn(s) reacts with 30.0 mL of 1.0 M HCl, the H2 gas produced is collected in a 1.0 L flask at a temperature of 270 K. What is the pressure (atm) of H2 gas collected? Zn(s) + 2HCl(aq) = ZnCl2(aq) + H2(g)

Chemistry
Would the percent yield of Ni(NH3)nCl2 be high, lower, or unchanged if you made the following procedural changes? a) You performed the synthesis reaction at 100 degrees instead of 60 degrees b) you dissolved the NiCl2*6H2O in 50 mL of distilled water instead of 10mL c) You did...

Chemistry
When 0.010 moles of Zn(s) reacts with 30.0 mL of 1.0 M HCl, the H2 gas produced is collected in a 1.0 L flask at a temperature of 270 K. What is the pressure (atm) of H2 gas collected? Zn(s) + 2HCl(aq) = ZnCl2(aq) + H2(g)

chemistry
25cm3 of a solution of NaOH required 28cm3 of 1.0mol/dm3 H2SO4 to neutralise it: a) write an equation for the reaction. b) how many molesof H2SO4 were needed? c) how many moles of NaOH were thus nuetralised?

Chemistry
When 0.010 moles of Zn(s) reacts with 30.0 mL of 1.0 M HCl, the H2 gas produced is collected in a 1.0 L flask at a temperature of 270 K. What is the pressure (atm) of H2 gas collected? Zn(s) + 2HCl(aq) à\longrightarrow ZnCl2(aq) + H2(g)

Chemistry
If the half life of a reaction A is 2 mins,how long will it take A to reach 25% of its initial concentration ?

Chemistry (Urgent)
Ksp of PbI2 at 25 degrees celcius and 15 degrees celcius is 7.5×10^-8 and 7.5×10^-9 respectively. (Pb=207 I=127) 1) write an expression for the equilibrium of PbI2 2)write an equation for the Ksp of PbI2 3)calculate the solubility of PbI2 at 25 degrees celcius in gdm^-3 4)...

Chemistry
My school notes say : pH < pOH is acidic pH > pOH is basic Is this correct, I was thinking that if the pH is less than pOH than it was a basic solution

Chemistry
Calculate the wavelength of nitrogen molecule travelling with a speed of 500 m/s

Chemistry
If a chemical reaction uses 140 g of N2. How many moles is this? n=m/M

Chemistry
Suppose a student diluted and titrated a bleach unknown exactly as described in the experimental procedure, except only a single titration was performed which required 16.22 mL of 0.100 M Na2S2O3. Calculate the number of moles of Na2S2O3 used in the titration.

CHEMISTRY: HESS'S LAW need help!
I'm just overly confused on how to begin this especially with the fractions... please show step by step if you could. Quiz very Soon! Example A: H2(g)+1/2 O2 (g) ----> H2O(l) ... ΔH= -285.8 kJ N2O5(g) + H2O(l) -----> 2HNO3(l) ΔH= -76.56 kJ 1/2 N2(g) + 3/2 O2(g) +1/2 H2...

chemistry
what is the net ionic equation for AlBr3(aq) + 3LiOH(aq)

Chemistry
Use the concentrations and volumes of hydrogen peroxide and KI before mixing (Table 1), calculate the post-mixing concentrations. Before mixing: [H2O2] = 0.88M [KI] = 0.500M Table 1: before mixing 1. Vol H2O2 = 4.0 mL, [H2O2] = 0.88M 2. Vol KI = 1.0 mL, [KI] = 0.500 M units: M...

chemistry
THE QUESTION ASKS TO CALCULATE THE AMOUNT (IN GRAMS) OF CARBON DIOXIDE FROM THE AMOUNT OF SODIUM BICARBONATE THAT YOU USED IN THE REACTION Run 1. The reaction of citric acid and sodium bicarbonate is written as H3C6H5O7(aq) + 3 NaHCO3(aq) → Na3C6H5O7(aq) + 3 H2O(l) + 3 CO2(g...

Chemistry
Tooth enamel consist mainly of hydroxyapatite (Ca5(PO4)3(OH). When tine (II) Flouride is added to toothpaste it reacts with the enamel to product a more decay-resistant material fluorapatite (Ca(PO4)3F. The by-products of this reaction are tin (II) oxide and water. What mass ...

Analytical Chemistry
A solution is prepared by dissolving 0.2222 (¡¾0.0002) g of KIO3 in 50.00 (¡¾0.05) mL. (i) Calculate the molar mass of KIO3 with its associated uncertainty to the correct number of significant figures. (ii) Find the molarity and its uncertainty with an appropriate number ...

chemistry
Write the reactants and products of the reaction between zinc and oxygen. Include the half-reactions. What type of reaction is this? I know the reaction is 2Zn + O2 -> 2ZnO I am not really sure where to go from here.

Chemistry
Calculate the mass of solid AgNo3 that can be added to 2.0 L of 0.10M K2CrO4 solution in order to just start precipitation? Here is what I have done so far: 2AgNO3(aq) + K2CrO4(aq) ==> Ag2CrO4(s) + 2KNO3(aq) Ag2CrO4(s) ===> 2Ag^+ CrO4^^2- Ksp = [Ag^+]^2[CrO4^2-] Ksp = (...

chemistry
A student dissolves a .726 g aspirin tablet in water and titrates the solution with .272 M NaOH are required to reach the equivalence point. Calculate the percentage of acetylsaliclic acid in the tablet. I am not really sure where to start with this. I unfamiliar with problems...

Chemistry
Calculate ΔG at 25°C for the precipitation of lead(II) iodide from mixing 100. mL of 0.10 M lead(II) nitrate solution with 100. mL of 0.10 M sodium iodide solution. The ΔG° for this precipitation reaction at 25°C = −46.2 kJ/mol.

Chemistry
Thanks to Dr. Bob for answering all these questions! I always do poorly on conceptual problems. Consider the following equilibrium system at 25°C and select the true statement below: H2PO4−(aq) + SO42−(aq) ↔ HSO4−(aq) + HPO42−(aq) ΔG°rxn > 0 at 25°C (1) this ...

Chemistry
Silicon Carbide, SiC, is prepared by heating silicon dioxide in the presence of graphite. Carbon dioxide is the by-product of the reaction. How many grams of silicon carbide can be formed from the reaction of 50.0 grams fo graphite with 50.0 grams of silicon dioxide?

Chemistry
Classify the reaction type (formation, simple composition, decomposition, combustion, single replacement, double replacement) and predict the balance equation 1. AL(s) + 02(g) ------> 2. Ag2O(s)------> 3. Br2(1) + KI(aq) ------->

Chemistry
Give an example of each of the following reactions, showing balanced equations for reactants= products and show s, I, g, or aq A.) synthesis B.) decomposition C.) single replacement D.) double replacement E.) neutralization F.) combustion

Chemistry
A scientist studying the reaction between decaborane (B10H18) and oxygen mixed 1.00 x 10^2 grams of decaborane with 2.75 x 10^2 grams of oxygen. Compute the masses of all substance present after the reaction went ot completion, generating B2O2 and water as the only products.

Chemistry
Calculate the mass of solid AgNo3 that can be added to 2.0 L of 0.10M K2CrO4 solution in order to just start precipitation?

chemistry
The alcoholic fermentation of350 g/l glucose syrup ceases when the alcoholic degree of the mixture attains 16º (16ml ethanol in 100ml of the solution) Write the reaction of the fermentation reaction. Consider the fermentation of 100L of the glucose syrup. Determine the volume...

Chemistry
What is the approximate ratio of the solubility of CaSO4 (Ksp = 2.4 x 10−5) in pure water to the solubility of CaSO4 in 0.10 M Na2SO4 at the same temperature?

Chemistry 2
A scientist studying the reaction between decaborane (B10H18) and oxygen mixed 1.00 x 10^2 grams fo oxygen. Compute the masses of all substances present after the reaction went to completion, generating B2O3 and water as the only products.

chemistry
Help me conclude my lab experiment on formula of a hydrate.with the aim of determine the number of molecules of water associated with a hydrated inorganic salt

Chemistry
At 3745°C, K = 0.093 for the following reaction. N2(g) + O2(g) equilibrium reaction arrow 2 NO(g) Calculate the concentrations of all species at equilibrium for each of the following cases. (a) 2.0 g N2 and 3.0 g O2 are mixed in a 1.3-L flask. [N2] [O2] [NO] (b) 1.5 mol pure...

Chemistry
An organic compound on analysis gave C=57.8% and H=3.6% and rest of oxygen.The vapour density of the compound was found to be 83.Find the molecular formula of the compound?

Chemistry
A sample of a substance (containing only C, H, and N) is burned in oxygen. 7.961 g of CO2, 1.164 g of H2O and 1.551 g of NO are the sole products of combustion. What is the empirical formula of the compound?

Chemistry
Calculate how many moles of Na2S2O3 must be added to dissolve 0.020 mol AgBr in 1.0 L of water at 25°C (assume constant volume). AgBr(s) ↔ Ag+(aq) + Br−(aq) Ksp = 3.3 x 10^−13 Ag+(aq) + 2S2O32−(aq) ↔ [Ag(S2O3)2]3−(aq) Kf = 2.0 x 10^13 (1) 0.0078 mol (2) 0.048 mol...

Chemistry
How many hydrogen atoms are present in 6.49 moles of hydrogen molecules

Chemistry
When mixing 10m/L of 6 M HCl (diluted with 10 mL of water) with 0.1 g of Mg, how many moles of H2 are created and how many moles of Mg are reactant? I understand I must use n=(PV)/(RT) to find H2, since it is a gas, but the constant R is still confusing to me and I cannot ...

Chemistry
A forensic scientist is given a white substance that is thought to be cocaine. The substance is found to have a percent composition: 49.48% C, 5.19% H, 28.85% N, and 16.48% O. What is the empirical formula for this substance? Is it cocaine?

chemistry
describe briefly a suitable laboratory procedure for separating a mixture of NaCl4,NH4Cl and PbCl2

chemistry
Under the same condition of temp.and pressure hydrogen gas diffuses 8 times as fast as gas y.calculate the relative molecular mass of gas y.(R.M M_2

chemistry
A certain amount of gas occupy 5.0dm cube at 2atm.and 10 degree centigrade .calculate d number of mole present(R_0.082atm)

chemistry
Under the same temp.and pressure ,nitrogen gas diffuses 8 times as fast as gas y .calculate the relative molecular mass of gas y.

CHEMISTRY
Determine the concentrations of Na2CO3, Na , and CO32– in a solution prepared by dissolving 2.22 × 10–4 g Na2CO3 in 2.25 L of water. Express all three concentrations in molarity. Additionally, express the concentrations of the ionic species in parts per million (ppm). ...

chemistry
How much energy is evolved during the formation of 98.7 g of Fe, according to the reaction below? Fe2O3(s) + 2 Al(s) → Al2O3(s) + 2 Fe(s) ΔH°rxn = -852 kJ A. 482 kJ B. 753 kJ C. 1.51 × 10ee3 kJ D. 4.20 × 10ee3 kJ

Chemistry
Calculate the molarity of the H2SO4 solution if 17.45 mL of NaOH was necessary to reach the endpoint of titration. The molarity of the NaOH solution was 0.425 M and 26.30 mL of H2SO4 was added to the Erlenmeyer flask. H2SO4(aq) + 2 NaOH (aq) -----> Na2SO4 (aq) + 2 H2O (l) I...

chemistry
hw much 0.1N NaoH would u have added to 30ml of 0.1N Hcl at a equivalent point?

Chemistry
Hydrogen iodide decomposition via a second-order process to produce hydrogen and iodine according to the following chemical equation: 2 HI(g) -> H2 (g) + I2 (g) If it takes 489 seconds for the initial concentration of HI to decrease from 0.0693 M to 0.0174 M, what is the ...

Chemistry
sulfuric acid can be prepared by a multistep process summarized as: 2 SO2 + O2 + 2 H2O--> 2 H2SO4 What mass of sulfuric acid could be produced daily by a process using 38 kg per day of sulfuric dioxide with a 70% conversion efficiency ("yield"), assuming that sulfuric ...

Chemistry
How many grams of a solid mixture containing strontium chloride would one need to make 558 mL of a 0.100 M strontium chloride solution, if the solid mixture contains 58.6% strontium chloride by weight

Chemistry
High-pressure sodium vapor lamps are used in street lighting. The two brightest lines in the sodium spectrum are at 589.00 and 589.59 nm. What is the diffrence in energy per photon of the radiations corresponding to these two lines?

Chemistry
Calculate the energy needed to ionize an electron of H atoms from its second excited state.

Chemistry
A hydrogen atom in one of its excited states ha an energy of -1.5129^20 J. What is the frequency of radiation is emitted when the atom relaxes down to its ground state?

Chemistry
Consider a 1.0 L container of Neon gas at STP. Will the average kinetic energy, average velocity,and frequency of the collisions of gas molecules with the walls of the container increase, decrease, or remain the same under each of the following conditions? a. The temperature ...

Chemistry
A compressed gas in a cylinder contains 1000.0 g of argon gas. The pressure inside the cylinder is 2050 psi at 18 degrees Celcius. How much gas remains if the pressure is decreased to 650. psi at a temperature of 26 degrees Celcius?

chemistry, science
how many moles of he atoms are there in 0.02g of he?

chemistry
A 75.0g sample of liquid contains 17.5% by mass of H3PO4 (molar mass = 98.0g/mol). If 215.0mL of Ba(OH)2 is needed to completely neutralize the acid, determine the concentration of the Ba(OH)2 solution used

Chemistry
Determine the concentration for the following solutions 2.0g KOH is dissolved in water to make 200.0 ml of solution

Chemistry
How much energy (in kj) is required to ionize 2.78 moles of hydrogen atoms the right answer is: 3.65x10^3 kj wondering how they got this answer.

Chemistry
Calculate the ionization energy (in kj) for a mole of hydrogen atoms, making the assumption that ionization is the transition from n=1 the correct answer is : 1.31x10^3 kJ

Chemistry
When 25g of ice lose 2092 J of heat at 0 degrees Celsius, what will be the new temperature of the ice? Calorimetry problem

chemistry
already missed question so I just need help figuring out what I did. Small amounts of chlorine gas can be gener- ated in the laboratory from the reaction of manganese(IV) oxide with hydrochloric acid: 4 HCl(aq) + MnO 2 (s) → 2 H 2 O( ℓ ) + MnCl 2 (s) + Cl 2 (g). What mass ...

Chemistry
what is the minimum uncertainty in the position of an electron moving at a speed of 4 x 10^6 m/s ± 1 %? I keep getting 1.44 x10^-11 m, but the right answer is 1x10^-9 m.

chemistry
how can i determine via infrared spectrum whether the alcohol that was oxidized was primary or secondary? i did a lab experiment in which we oxidized a diol with bleach and i need to figure out which -OH group was oxidized into a C=O. What are the signs of whether the -OH is ...

Chemistry
4.72 g of a compound of carbon, hydrogen, and silver was burned in an atmosphere of oxygen, yielding 7.95 g of CO2, 1.02 g of H2O and 3.02 g of a mixture of silver and silver oxide. Because the production of this mixture yielded an indeterminate value for the amount of silver...

Chemistry
Can geranium be used to detect infrared radiation emitted by a remote control device that has a wavelength of 902 nm? the work function (binding energy) of geranium is 7.61 x10^-19 J?

chemistry help, urgent!
Which of the following should you add to stabilize the pH of a solution? solute acid <<my choice buffer base

Chemistry
the lead (II) nitrate in 25.49 ml of a 0.1338M solution reacts with all of the aluminum sulfate in 25.00 ml solution. What is the molar concentration of the aluminum sulfate in the original aluminum sulfate solution? For a question like this how do I find out it is a 3:1 ratio...

Chemistry Help
The most effective buffer solutions have equal concentrations of salt and acid (or base). Find the pH of a buffer solution with equimolar concentrations of: (a) HCOOH and NaCOOH (Ka = 3.5 x 10-4 for HCOOH) (b)CH3NH2 and CH3NH3Cl (Kb = 3.7 x 10-4 for CH3NH2) Thank you!

Chemistry
Calculate the molar mass of a molecular compound if a solution of 6.70 g of the compound in 22.60 g of water boils at 100.78 degrees C (at 760mmHg).

Chemistry
A is a solution of hydrochloric acid containing 3.650g of HCl in 1dm3 of solution. B is a solution of impure sodium carbonate. 25cm3 of B require 22.7cm3 of A for complete reaction. Given that 5.00g of impure B was dissolved in1dm3 solution,what is the percentage by mass pf ...

Chemistry
How much ethylalcohol must be added to 1litre of water so that the solution will freeze at 14 farenite, kf of wa ter is 1.86 c/mol

Chemistry
the lead (II) nitrate in 25.49 ml of a 0.1338M solution reacts with all of the aluminum sulfate in 25.00 ml solution. What is the molar concentration of the aluminum sulfate in the original aluminum sulfate solution?

chemistry
calculate the volume of hydrogen that will combine with 40 litres of oxygen to form steam at 150°C and atmospheric pressure?

Chemistry
Compound A consisting of carbon and hydrogen only. The compound was found to contain 80% carbon by mass,cal. its empiri.

Chemistry
Find the ratio of the volumes of NaC3H5O3 soloution to HC3H5O3 (lactic acid) required to prepare a buffer with a pH of 3.90. the solutions are equal in molarity. Ka = 1.4 x 10-4 for HC3H5O3. ratio = ________ mL of NaC3H5O3 per mL of HC3H5O3

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