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Homework Help: Science: Chemistry

Recent Homework Questions About Chemistry

chemistry
Water, compared to other substances, has one of the highest specific heat values. What is the advantage of this fact for the human body? -Thank you ☺

Chemistry
Determine the Enthalpy of combustion of ethyne (C2H2) using the following enthalpies of formation; Data: DHf°(H2O)= -285.9kj/mol DHf°(2H2)= +226.7Kj/mol DHf°(CO2)= -393.5Kj/mol Equation; C2H2--------->CO2 + H2O

Chemistry
Write a balanced equation for the reaction that occurs in each of the following cases. (Use the lowest possible coefficients. Include states-of-matter under SATP conditions in your answer.) I think have the reactions, but I'm stuck with the states of matter. Any help would be ...

Chemistry
In a titration experiment what would be the result on the concentration of the analyte if the drop counter did not count all the drops? would it be lower since you would just be calculating the concentration at the same point on the curve just with a lower volume of titrant?

Chemistry
Which statement is always true if ΔU sys is always negative? a) q = w b) +q>–w c) -w> +q d) +w>-q

Chemistry
Identify which of the following changes is exothermic. a) liquid water boils to steam b) liquid water freezes to give ice c) ice melts to give liquid water d) liquid water increases in temperature from 35 C to 45 C

Chemistry
what volume of oxygen is needed to react to complete reaction and to form 5cm of so3?

Chemistry
How to calculate the percentage of chlorine isotopes

Chemistry
What's the resulting solution if 2000cm3 of 1MH2S04 is mixed with 20cm3 of 1M NaOH? i got 0.5M,acidic in concentration.

Chemistry
The relationship between velocity(U) of a gas molecules and their relative molecular mass(RAM) is?

Chemistry
what is the relative atomic mass of a silicon containing ore with 92% 28'Si,5%29'Si and 3%30'Si?

Chemistry
At 25 degree celsius, which balloon has the greater volume, an oxygen balloon O2 at 1.2 atm with a mass of 16.0 g, or helium He balloon at 1.2 atm with a mass of 2.0 g?

Chemistry
Can someone check my answer and let me know me if the are right or wrong. If I wrong can you give me the right answer plz. 1. What is the maximum amount of KCl that can dissolve in 600 g of water? (The solubility of KCl is 34 g/100 g H₂O at 20°C.) * 34 g 204 g 56 g******* ...

Chemistry
what mass of h2o is formed when h2 reacts with 384g of o2?

Chemistry
Which of these will have a volume of 22.4 L at STP? A) 12.01 g of C(s) B) 16.4 g of CH4(g) C) 36.46 g of HCl(aq) D) 32.05 g of CH3OH(l) E) 22.00 g of CO2(g) I am not really sure how to verify that a particular substance will be at these conditions.

Chemistry
In the analysis of a sample of drinking water, a rate of 25.00 mL of the water requires 16.04 mL of AgNO3 to 0.05647 M in order to achieve an end to the Mohr method. What is the concentration of chloride ions in the sample?

Chemistry
I’m trying to precipitate out FePO4. Following the reaction: H3PO4 + FeCl3 = FePO4(s) + 3HCl I reacted phosphoric acid to ferric chloride, and according to the reaction, there should be a precipitate. But I haven’t observed a precipitate for the last 3 hours. Is there a ...

Chemistry
What mass of glucose (C6H12O6) must dissolve in 400.0 g of ethanol to make a 1.60 m solution?

chemistry
name an invention or event (related to science or technology) from the past 100 years that you think has helped shape the roles of women today.

chemistry
what mass of gold can you extract from 34.94g of AuCl3 using electrolysis of an aqueous solution?

Chemistry
What volume of N2O (s) will be generated if 3.13 g of NH4NO3 (s) decomposes at 1.00 atm and 50 degrees celsius, given the following decomposition reaction: NH4NO3 (s) --> N2O (g) + 2 H2) (l)?

Chemistry
Given the reaction: Fe2SiO4 (s) + 2 H2CO3 (aq) ---> 2 FeCO3 (s) + H4SiO4 (aq) how many grams of Fe2SiO4 (s) are required to completely react with 55.0 mL of .500 M H2CO3 (aq) ?

Chemistry
Calculate the H+ concentration (M), the OH- concentration and the number of H+ and OH- per litre in solutions having pH value of 2.73

chemistry
Which of the following bases is the weakest? 1)(CH3)2NH , Kb = 5.1 x 10–4 2)ClO–, Kb = 2.9 x 10–7 3)SO42–, Kb = 8.3 x 10–13 Im thinking the answer is 2, but im not100%

Chemistry
Second orbital is ......... Away from nucleus present Ina subshell that is represented by azimuthal quantum number = 3 will be

Chemistry Help?
Can someone walk me through the steps on how to solve using these equations? Thank yoouuuu~~ 1.11g of methane CH4 is burned in a bomb calorimeter containing 1000 grams of water. The initial temperature of water is 24.85oC. The specific heat of water is 4.184 J/g oC. The heat ...

Chemistry
A second order reaction is 50 % complete in 16 minutes. How long will it take to be 82 % complete

Chemistry
Given the reaction: Fe2SiO4 (s) + 2 H2CO3 (aq) ----> 2FeCO3 (s) + H4SiO4 (aq). How many grams of Fe2SiO4 are required to completely react with 55.0 mL of .500 M H2CO3 (aq)?

Chemistry
What would be a good chemical blank to use for the Tollen's Test (Silver Mirror test)?

Chemistry
WHAT ARE THE MAJOR SPECIES PRESENT IN A AQUEOUS SOLUTION OF 1.0M CH3C00H? I) CH3COOH II) H20 III) H30+ IV) CH3COO- VI) OH-

Chemistry 30
How do i do this question?? A 10.00ml Sample was taken from a 2Liter Container of Tropicana Orange juice. This sample was analyzed for its citric acid content by titration with a known 0.1112M NaOH base solution. A Phenoolphthalein indicator was added to detect the endpoint ...

chemistry
At 983 torr of pressure, 1.62 grams of a gas dissolves in 2.0L of water at 10'C. What mass of gas will dissolved in 2.0L of water at 1432 torr and 10'C

Chemistry
Write the equations for the reactions in which acids and bases are neutralized by the buffer consisting of HCOOH and HCOONa is a water solution in order to maintain a relatively constant pH of the solution?

chemistry
1. 25.0mL of 0.20M Propanic acid (HC3H5O2, Ka = 1.3×10-5) is titrated using 0.10M NaOH. Calculate the following pH. Show your work. a. When 0.0 mL NaOH is added. b. When 25.0 mL NaOH is added c. When 50.0 mL NaOH is added d. When 75.0mL NaOH is added.

Science: Chemistry
What is the mass percent of oxygen in sodium bicarbonate(NaHCO3)?

chemistry
Calculate the concentration of all species in a 0.20 M KF solution.

Chemistry
Given that 10.0 atm each of NO and O2 are introduced into a reaction vessel at room temperature. Calculate the partial pressure of each gas at equilibrium. 2NO(g)+O2 (g)---> 2NO2 (g) Kp =4.2x1012. at. roomtemperature. To solve this question I need to find limiting reactant...

Chemistry
Ross pours water at 6.0 C into a container with a pressure of 23. torr. He then boils the water to a temperature of 34 C. The volume changes to 18. mL and pressure to 78. torr. What was the initial volume of the water?

chemistry
An empty beaker weighs 39.17 g. a) When completely filled with water, the beaker and its contents have a total mass of 406.25 g. What volume does the beaker hold? Use d =1.00 g/mL as the density of water. for A i got 367.08 but I don't know for this b) How much would the ...

Chemistry
An unsealed 750 mL beaker contains 500 mL of very dense gas at 25.0 degrees C and 1.10 atm. The gas is much denser than the surrounding air, so it does not disperse into the air. (a) At constant pressure, what would the temperature have to reach for the gas to fill the beaker...

Chemistry
Ross pours water at 6.0 C into a container with a pressure of 23. torr. He then boils the water to a temperature of 34 C. The volume changes to 18. mL and pressure to 78. torr. What was the initial volume of the water?

Chemistry
When a person got onto an airplane, she brought with her a half-full 1.0000 L aluminum water bottle that was closed inside the airport at standard pressure and a temperature of 26.000 C. After the plane takes off and climbs to 36,000. feet, the cabin pressure is at 0.82000 atm...

Chemistry - Gravimetry
If 0.8000 g of a mineral yields 0.2400 g of NaCl + KCl, and this mixture contains 58.00% of Cl, what is the percentage of Na2O and K2O in the mineral? I already tried solving it and I got 12.69% Na2O and 3.84% K2O. However, I checked the answer key and the answers there are ...

Chemistry
The element in the period 2 group 6 gains/ loses ______ electrons to become a cation/ anion?

Chemistry
Why doesn't acetylation occur twice on the same ring? Please help, I have no idea.

chemistry
help please write the phases for the following equation Sr(NO3)2+2KIO3+H2O-----> Sr(IO3)2*H2O+2KNO3 and also write the net ionic equation

Chemistry Lab
*The decomposition of acetaldehyde is a first order reaction with a specific rate constant of 6.0 X 10^-1 / min. CH₃CHO --> CH₄ + CO 1. Calculate the initial rate when the concentration of acetaldehyde is 0.80M. 2. Calculate the time needed for the concentration of the ...

Chemistry
Identify the chemical reactants in ZnCl2(aq)+H2(g)?

Chemistry
Which pair of reactants will not react? Au(s) with Hg^2+ (aq) Pt^2+ (aq) with Au(s) Ag(s) with Cu(s) Au(s) -> Au^3+(aq) + 3e- Hg(s) -> Hg^2+(aq) + e- Pt(s) -> Pt^2+(aq) + 2e- Cu(s) -> Cu^2+(aq) + 2e- My guess is all of them, but I am not entirely sure.

Chemistry
Using the following portion of the activity series for oxidation half-reactions, determine which element(s) can react with an acid to produce H2 gas. Co(s) → Co^2+ (aq) + 2e- Ni(s) → Ni^2+ (aq) + 2e − Sn(s) → Sn^2+(aq) + 2e - H2 (g) → 2H+ (aq) + 2e − Cu(s) → Cu^2...

chemistry
Determine the order of reducing agents (strongest to weakest). A) Mn(s) > Zn(s) > Cr(s) > Fe(s) B) Fe(s) > Cr(s) > Zn(s) > Mn(s) C) Mn(s) > Fe(s) > Cr(s) > Zn(s) D) Zn(s) > Mn(s) > Cr(s) > Fe(s) I know the half reaction for the following: - ...

Chemistry
T/F The absorption lines of neon occur at slightly different wavelengths than its emission lines. My answer: I thought that they would have the exactly opposite wavelengths? Am I missing something?

Chemistry
Rank the bonds between the listed atoms from most ionic to most covalent: -AlO -CN -SCl -KF

chemistry
A mixture of H2(g) and N2(g) has a density of 0.221 g·L−1 at 301 K and 501 torr. What is the mole fraction composition of the mixture?

chemistry
a piece of copper weighing 400g is heated to 100degree celsius and then quickly transfered to a copper calorimeter of mass 10g containing 100g of liquid of unknown specific heat capacity at 30 degree celsius.if the final temperature of the mixture is 50 degree celsius,...

Chemistry
Does every neutral helium atom in the universe have the same set of absorption lines as every other neutral helium atom (with the same atomic mass)?

Chemistry
draw the product of di-acetylation of biphenyl. Explain why acetylation does not occur twice on the same ring. I have no idea how to do this

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.

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