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Homework Help: Science: Chemistry

Recent Homework Questions About Chemistry

Chemistry
A beaker of nitric acid is neutralized with calcium hydroxide. Write a balanced molecular equation and a net ionic equation for his reaction

Chemistry
What effect does the presence of an impurity have on the freezing point of a liquid?

Chemistry Lab
Number of moles of HCl and Na2CO3 (show calculations) when 0.015 g of Na2CO3. How can I calculate this problem if I am only given the 0.015 grams of Na2CO3?

CHEMISTRY
15.0g of KCLO3 was crushed and heated with about 0.1g of MnO2.Write an equation for the reaction.

Chemistry
When an electric current passes through water during the process of electrolysis, two gases are formed. One gas has a boiling point of -183 C and the other has a boiling point of -253 C. Has a physical change or chemical change occurred? Explain. I think it is a chemical ...

Chemistry
Write the formulas of the compounds formed by NH4+ with the following anions: NO3−, HCO3−, SO42−, HPO42−. Express your answers as chemical formulas separated by commas. Use the given order of anions.

chemistry
what is the pH of a solution prepared by adding 0.65mol of LiOH(aq) to 1.0L of 0.30mol/L HNO3(aq)>

Chemistry
A student does a standard addition experiment by pipetting 25 mL of unknown, adding ferrous ion spikes and reagents, into a 100 mL volumetric flask and making up to the mark. The equation of the line has a slope of 0.103 and an intercept of 0.135 when the unit of concentration...

Chemistry
Each increase in pressure of 100 atm decreases the melting point of ice by about 1.0¡ÆC. Q. One possible explanation of why a skate moves smoothly over ice is that the pressure exerted by the skater on the ice lowers its freezing point and causes it to melt. The pressure ...

Chemistry
An Unknown Compound (M=60.09 g/mol) is composed of Carbon, Hydrogen and Oxygen. Combustion of 0.255 g of the unknown compound produces 0.561 g Carbon Dioxide and 0.306 g of Water. Determine the molecular formula of the compound.

General Chemistry
A typical human adults exhales 500 mL of air per breath. At this rate, calculate the volume of air exhaled after 20 breaths in units of cubic meters.

Chemistry
Calculate the amount of energy released in the formation of one mole of MgSe bonds (not lattice energy). The radius of the magnesium ion is 0.65 Å, and the radius of the selenide ion is 1.98 Å. Note that 1Å=10^−10m. I know I need to use the formula E=k(q1*q2)/d ...

Chemistry
What mass of Na2S is produced when 20g of sodium reacts with excess sulfur?

Chemistry
Ammonia (NH3) reacts with oxygen to produce nitric oxide (NO) and water (see balanced equation below). How many grams of oxygen do you need to react with 21.4 g ammonia? __4_NH3 + __5_O2 → __4_NO + _6__H2O

Chemistry
can you please please help me with these questions I don't know how to do any of them. I know how to calculate moles and grams and mole ratio,etc but I don't understand the limiting excess reactant and yield stuff. Thanks! 1.In the following chemical reaction, how many grams ...

Chemistry
To prepare a solution of NaCl, you weigh out 2.634 (0.002)g and dissolve it in a volumetric flask whose volume is 100.00 (0.08) mL. Express the molarity of the solution, along with its uncertainty.

Chemistry
can you please please help me with these questions I don't know how to do any of them. I know how to calculate moles and grams and mole ratio,etc but I don't understand the limiting excess reactant and yield stuff. Thanks! 1.In the following chemical reaction, how many grams ...

AP Chemistry
A 12.8 g sample of iron ore is treated as follows. The iron in the sample is all converted by a series of chemical reactions to Fe2O3. The mass of Fe2O3 is measured to be 21.3 g. What was the mass of iron in the sample of ore? Answer in units of g.

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 1 and 2 only 2 and 3 only 1 and 3 only All of 1, 2, and 3 None of 1, 2, and 3

Chemistry
The mass of potassium iodate (KIO3) contained in an impure sample was determined by titration with sodium thiosulfate (0.1005 M). The impure KIO3 was dissolved in 50 cm 3 of water, an excess of potassium iodide (KI) and 5 cm^3 of dilute sulphuric acid was then added. At the ...

Chemistry
Prepare 30mL of a stock KI soln by mixing 10.0mL of the 0.03M KI in 0.2M KNO3 with 20.0mL of the .2M KNO3 Determine the concentration of the iodide ion. What does it mean by the 0.03M KI in 0.2M KNO3? Is this just bad wording of the question? Am I just mixing the 10.0mL of ....

Chemistry
A student prepares a soln that is initally 0.006M Pb2+ and 0.00450M I-. This soln is placed into a 1.00cm wide cuvet and inserted into the spectrometer producing as abosrbance reading of 0.430 at a wavelength of 456nm. What is the equilibrium concentration of the iodide ions ...

Chemistry
What specific evidence from the gold foil experiement led Rutherford to come to each of the following conclusions? The nucleus occupies very little space in the atom. Answer:He shot alpha particles through thin sheet of gold and discovered some were deflected An atom is made ...

chemistry
A 1.60 g sample of a mixture of naphthalene, C10H8, and anthracene, C14H10, is dissolved in 20.0 g benzene, C6H6. The freezing point of the solution is 2.81oC. What is the composition as mass percent of the sample mixture?

Chemistry
3. What experimental problems would confront you if you attempted to determine the concentration of the metal ions in solutions of each of the following reagents? a. Cr +3 which has a maximum absorbance at 407 nm with absorbtivity of 15 M -1 cm -1 and another at 574 nm with ...

chemistry
How can values of heats of formation found in tables be used to calculate heats of reactions? I am having a really hard time understanding this.

Chemistry
Calculate the amount of energy released in the formation of one mole of MgSe bonds (not lattice energy). The radius of the magnesium ion is 0.65 Å, and the radius of the selenide ion is 1.98 Å. Note that 1Å=10^−10m. I know I need to use the formula E=k(q1*q2)/d ...

chemistry
How much energy is required to make H2O(g) from H2O(l)? Basically this deals with bond energies and heats of formation. But I'm not sure how to find it

chemistry
What is n+1+m for 4p orbital and what is n+l+m for 4p orbital

chemistry
For a skydiver jumping out of a plane at an altitude of 1 km, what would be the concentration of oxygen in his (or her) blood knowing that air pressure at 1 km drops to 89,874 Pa? Assume ideal behavior of gases, normal breathing, 25 °C and constant air composition. Hint: ...

CHemistry
What is the molecular formula of glycerol (a compound containing C, H, and O) from the following combustion analysis: when 2.00 g glycerol are combusted, 2.865 g CO2 and 1.564 g H2O are recovered. I already found uts molar mass its 92g/mol

Analytical chemistry
A solution is created using 2.1700 grams of Calcium Hydroxide (MW is 74.093) in a 1L volumetric flask. A 50 mL aliquot is then taken and aded to a 350 mL volumteric flask and filled to the line. Finally, a 10 aliquot of the that solution is taken and added to a 100 mL ...

Analytical chemistry
0.6140 grams of sodium phosphate (Na3PO4) was dissolved in 2 L of water to make a stock solution. 34 mL of this solution is then diluted to 100mL volumetrically to prepare the final solution. Calculate the molarity of phosphate ions in this solution. Answer to 5 decimal places.

CHEMISTRY
calculate the weight of co2 by complete combustion of 1.5 \g of ethane

Chemistry
In a titration 100 mL of 3.65 g HCl is added to 200 mL of BA(oh)2 solution of an unknown concentration until the equivalent point find molarity of ba(oh)2

Chemistry
A handbook gives the heat of combustion of liquid carbon disulfide as -3.42 kcal/g of the liquid. Write the equation representing the combustion of 1 mol of carbon disufide and the accompanying ΔH value. (hint: the sulfur containing combustion product is sulfur dioxide).

Chemistry
Calculate the heat capacity of a sample of radiator coolant if a temperature rise from 5 to 107℃ requires 932 J of heat. My work: c=q/mΔT c=932J/(?)(107℃-5℃)

Chemistry
Tin and purple Iodine combine to form an orange solid tin iodide compound. If the compound contains 0.00383 moles of Sn and 0.01534 moles of I, what is its' empirical formula?

chemistry
I got this question wrong it was true/false the answer was false A supersaturated solution will have some solid undissolved in the bottom of the container. I don't know why its false?

Chemistry
I'm doing online homework and the follow question has come up: Write the formulas of the compounds formed by Pb4+ with the following anions: NO3−, ClO3−, SO32−, H2PO4−. Express your answers as chemical formulas separated by commas. Use the given order ...

chemistry
List the following strong electrolytes solutions in order of increasing boiling point. a. 0.1 M CaCl2 b. 0.1 M AlCl3 c. 0.1 M CaS

chemistry
 If we combine nitrous oxide (NO, laughing gas) with oxygen (O2) we produce nitrogen dioxide (NO2) according to the following reaction: 2NO + O2→ 2NO2 How many grams of NO2 will be produced when 5.00 moles of NO react?

chemistry
A solution containing 40 g of calcium bromide requires 14.2 g of chlorine to react completely with it and 22,2 g of calcium chloride is produced in addition to ehaever bromine is obtained. How many grams of calcium bromide are required to produce 10.0 pounds of bromine?

chemistry
Calculate the normality of solution containing 4g of sodium hydroxide present in 1 litre of solution ?

CHEMISTRY
I'm trying to figure out the percent composition of a mixture of an unknown (a combination of NaHCO3 and NaCl). Here's my data: Mass of 150mL of empty beaker: 80.937g Mass of 150mL beaker w/ unknown: 81.957g Mass of 150mL beaker w/ unknown after reaction: 89.126g Mass of ...

Chemistry
To clarify, a triple bond between carbon and oxygen is more stable than a triple bond between carbon and nitrogen because oxygen is more electronegative. Is my understanding correct?

chemistry
is heating iodine from its solid state to a liquid state a chemical or physical change?

chemistry
how many joules of heat are required to heat 149g of aluminum from 31.0 celcius to 75.5 celsius

Chemistry
I was given a solution of HCOOH with hand approximate concentration of 0.20 moles and I need to titrate this with a 0.110 V mol of NaOH. If I add 20 milliliters of hcooh to the beaker before I titrate approximately what volume of NaOH will be required to reach the endpoint?

Chemistry
Sample of 10.7g of O2 reacts completely with CO to form CO2 3a) How many grams of CO2 will be formed. So 10.7g (1mol/32g) (2molCO2/2molCO2)(22.01gCO2/1molCO2) = 14.7g. Please is this right 3b) is the mass of CO2 ypu determined in the equation (3a) the minimum or the maximum ...

Chemistry
74. Sodium hydrogen carbonate is also known as baking soda. When this compound is heated, it decomposes to sodium carbonate, carbon dioxide, and water vapor. Write the balanced equation for this reaction. What volume of carbon dioxide gas at 77 degrees C and 756 mmHg will be ...

Chemistry
Consider a mixture of two gases,A and B, confined in accosted vessel. A quantity of a third gas C, is added to the same vas sekar the same temperature. How does the addition of gas C affect the following: a. The partial pressure of gas A. b. The total pressure in the vassal, c...

Chemistry
You want to heat 1 kg of water 10 degrees celsius and you have the following methods under consideration. The heat capacity of water is 4.184 J/K g. (a) You can heat it with a mechanical eggbeater that is powered by a 1-kg mass on a rope over a pulley. How far does the mass ...

Chemistry
Which of the following compounds has an atom with an unfilled valence shell of electrons? A) H3O+ B) BF3 C) CH3OH D) NaI

Chemistry
Use bond energies to determine the energy transferred in the reaction between hydrogen and chlorine to make hydrogen chloride. H2 (g) + Cl2 (g) → 2HCl (g)

Chemistry
What volume of (2.5M) Hydrochloric Acid will be needed to neutralize 359mL of a 1.50M solution of potassium hydroxide?

Chemistry
How do you write the isotopic symbol for Uranium -238?

Chemistry
The half life of radon 222 is 3.82 days. If the initial mass of a sample of radon 222 is 198.72 grams, how much will remain after 19.25 days?

Chemistry
You want to heat 1 kg of water 10 celsius and you have the following methods under consideration. The heat capacity of water is 4.184 J/K g. (a)You can send the water through a solar collector that has an area of 1 m^2. How long will it take if the sun's intensity on the ...

Chemistry
A student performing an experiment mistakenly used 8.0 ml of 16 M HNO3 to dissolve 0.16g of solid copper instead of the 4.0 ml as suggested. how many moles of HNO3 remains after the reaction with copper is complete. 8 moles of HNO3 reacts with 3 moles of Cu im not sure how i ...

Organic Chemistry
Hi, I'm trying to fix an incorrect IUPAC name of a molecule. It is given as trisecbutylmethane, and I have to draw it out to correct it. Here's the thing: how do I draw incorrect IUPAC name? I can't wrap my mind around it. What I have drawn out is a tertiary carbon with 3 ...

chemistry
Write the anodic reaction for the electrolysis of zinc chloride solution using platinum electrode

Chemistry
The standard change in internal energy for the combustion of buckyball is -25,968 kJ/mol. What is the enthalpy of combustion? What is the enthalpy of formation of buckyball? What is the molar enthalpy associated with converting buckyball to graphite? How does this compare to ...

Chemistry
0.250 g KCN is dissolved in 50 mL of water, and added to 2 mL of NaOH then mixed with 48mL of water. What is the molar concentration of KCN? I am stuck on this question. So far I have: 0.250gKCN/0.050L= 5M(g/L) Moles of KCN: 5M = mol/0.05L = 0.25mol KCN I am not sure exactly ...

Chemistry
Write a net ionic equation for the overall reaction that occurs when aqueous solutions of potassium hydroxide and oxalic acid (H2C2O4) are combined.

Chemistry
How high can a person (assume a weight of 70 kg) climb on one ounce of chocolate if the heat of combustion (628 kJ) can be converted completely into work associated with vertical displacement?

chemistry
A compound contains 74,27%C;7,79%H;12,99%N. Determine the empirical formula. C=12;H=1;N=14;0=16.

chemistry
Calculate the percentage composition of sulphuric acid if the atomic masses are H=1u, S=32u and 0=16u

Chemistry
7. A student conducts an experiment on a different hydrate. The empty crucible is heated to a constant mass of 24.330. A sample of the unidentified hydrate is placed in the crucible, and the total mass is 31.571 g. The crucible and hydrate are heated to constant mass, which is...

chemistry
71.0 mL of a 1.30 M solution is diluted to a total volume of 238 mL. A 119-mL portion of that solution is diluted by adding 105 mL of water. What is the final concentration? Assume the volumes are additive.

Chemistry
What type of reaction is listed below? Prove that it is balanced by listing the number of elements on both side of the equation (reactants vs. products)? CH 3 COOH + NaHCO 3  NaCH 3 COO + H 2 CO 3 2. What type of reaction occurred with H 2 CO 3 from the above equation ...

Chemistry
If the concentration of KCN at the equivalence point is 0.1M and the Ka for HCN is 6.2*10^-10 find the pH at the equivalence point. The reaction is between KOH and HCN From my understanding I have to do a stoichiometric calculation and then use the Henderson-Hasselback ...

Chemistry
A 349mL sample of 1.659 M HI is mixed with 511 mL sample of NaOH (which has a pH of 13.35). What is the pH of the resulting solution?

Chemistry
1)Calculate the number of mL of a 0.095 M NaOH solution required to neutralize 25.0 mL of 0.15 M acetic acid solution 2) Calculate the molarity of a sodium hydroxide solution if 22.0 mL of the sodium hydroxide is required to neutralize 0.50 g of KHP. NaOH(aq)+ KHC8H4O4 -> ...

Chemistry
1)Calculate the number of mL of a 0.095 M NaOH solution required to neutralize 25.0 mL of 0.15 M acetic acid solution 2) Calculate the molarity of a sodium hydroxide solution if 22.0 mL of the sodium hydroxide is required to neutralize 0.50 g of KHP. NaOH(aq)+ KHC8H4O4 -> ...

Chemistry
Rank the following atoms in order of decreasing electronegativity, putting the most electronegative first: F, Ne, O, N, C

Chemistry
A 19.3L expandible container is filled in a room where the pressure is 761mmHg. It is filled with 600.4mmHg nitrogen, 108mmHg oxygen, 32.1 mmHg water vapor. The rest of the pressure is made up by carbon dioxide. The temperature is 20.3°C a. What is the partial pressure of ...

AP Chemistry
Given that the specific heat capacities of ice and steam are 2.06 J/g · ◦C and 2.03 J/g·◦C, respectively, calculate the total quantity of heat necessary to melt 19.2 g of ice at −50.0◦C and heat it to steam at 200◦C. The molar heats of fusion ...

Chemistry
Write the net ionic equation for the equilibrium that is established when ammonium nitrate is dissolved in water. (Use H3O+ instead of H+)

Chemistry
The concentration of ammonium ion in the solution of the salt called ferrous ammonium sulfate, formula [Fe(NH4)]2(SO4)3, is 0.360 M. The concentration of sulfate ions in this solution is?

Chemistry
A 349mL sample of 1.659 M HI is mixed with 511 mL sample of NaOH (which has a pH of 13.35). What is the pH of the resulting solution?

AP Chemistry
DrBob222 PLEASE HELP Hf of CO2 = -393.5 kJ/mol Hf of H2O = -285.8 kJ/mol The combustion reaction for benzoic acid C6H5CO2H(s) + 15/2 O2(g) → 7 CO2(g) + 3 H2O(ℓ) has ∆H0 = −3226.7 kJ/mole. Use Hess’s Law to calculate ∆H0f for benzoic acid. 1. &#...

Chemistry
A 635 mL solution of HBr is titrated with 0.51 M KOH. If it takes 1569 mL of the base solution to reach the equivalence point, what is the pH when only 141 mL of the base has been added to the solution?

AP Chemistry
Given that the specific heat capacities of ice and steam are 2.06 J/g ·◦C and 2.03 J/g·◦C,respectively, calculate the total quantity of heat necessary to melt 19.2 g of ice at −50.0 ◦C and heat it to steam at 200◦C. The molar heats of fusion and...

chemistry
write down the chemical formular for the following compounds 1.Sodium flouride 2.Berillium chloride 3.Pottasium iodide 4.Rubidium bromide 5.Magnesium sulphide

chemistry
if copper (II) sulfate pentahydrate is known to be 36% of water how many grams of water will be lost when heating a 5.75 grams sample?

Chemistry
You took 7.15 mL of the 2.20 M solution and diluted it. It's absorbance is 0.605. What is the concentration of the new solution? I have no idea where to even start.

Chemistry
Calculate volume of ammonia gas produced at STP when 140g of nitrogen gas is reacted with 30g of hydrogen gas.

Maths
In a class of 60students,the number of student passed Biology is 6 more than the number of student passed Chemistry,8 student passed both subject.How many student passed Biology,how many student passed Chemistry,how many student passed only one subject?

chemistry
The solubility of barium nitrate at 100°C is 34 g/100 g of H2O and at 0°C is 5.0 g/100g of H2O. If you start with 100 g of Ba(NO3)2 and make a saturated solution in water at 100°C, how much water is required? If the saturated solution is cooled to 0°C, how much Ba(NO3)2 is...

Chemistry
A 635 mL solution of HBr is titrated with 0.51 M KOH. If it takes 1569 mL of the base solution to reach the equivalence point, what is the pH when only 141 mL of the base has been added to the solution?

Chemistry
How many different oligosaccharides can be made by linking one glucose and one galactose if the anomeric carbon of glucose is involved in the glycosidic bond? Assume that each sugar is in its pyranose form. A. 5 B. 4 C. 2 D. 1 E. 3 Would it be 4?

Chemistry
The bond between a glycoprotein and a carbohydrate is made to which atom of a monosaccharide? A. C-3 B. C-6 C. varies with different glycoproteins D. anomeric carbon E. C-4 Would the answer be (E) C-4?

Chemistry
A 19.3L expandible container is filled in a room where the pressure is 761mmHg. It is filled with 600.4mmHg nitrogen, 108mmHg oxygen, 32.1 mmHg water vapor. The rest of the pressure is made up by carbon dioxide. The temperature is 20.3°C a. What is the partial pressure of ...

chemistry
A sample of neon gas is held in a rigid 2.284L container with a pressure of 1.036 atm at 24.3°C. 4.093g of an unknown cold gas is added to the container. The temperature drops to 20.3°C, but the pressure rises to 1.960atm. What is the molar mass of the added gas?

Organic Chemistry
Compound A has solubility at 20 degrees celsius of .029 g / 10.0 mL. How much of compound A will remain in solution after cooling to 20 degrees C?

Chemistry
Dr. Bob222 I still didn't understand which is the reduction half reaction and its products and oxidation half reaction...and why is it O3 to IO3-...0 to -6 and then Please help...entrance exam soon Write the oxidation and reduction half reactions(showing e- lost or gained) for...

Chemistry
Water drips from a faucet into a flask at the rate of two drops every 5 seconds. A milliter of water is 20 drops. What volume of water, in liters, will be collected in 2.5 hours.

chemistry
Calculate energy change that produced the 4th line in lyman series

chemistry
how many grams of barium would be found in 1.72g of barium sulfate 1.72(137.3/233.4)

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