# Laira

### I need help bad, pleaseeee!?

1. _________ produces a net migration of water only if the concentration of colloidal size particles is different on the two sides of the membrane.

2. What is the boiling point elevation of a solution of 222 g of ethylene glycol (C2H6O2) dissolved in 1000 g of water?

3. What is the freezing point of a solution of 137 g of ethylene glycol (C2H6O2) dissolved in 1000 g of water?

4. A sodium chloride solution with a concentration of 31.4 g/L is separated from pure water by an osmotic membrane. What is the osmotic pressure of the salt solution at 25°C? (R = 0.082 L-atm/K mol)

5. What is the osmolarity of a solution that has a concentration of NaCl of 0.344 mol/L?

1 AnswerChemistry8 years ago### Chemistry help needed, please!!!?

1.How many moles of sodium chloride are in 756 mL of a 2.43 M solution of sodium chloride?

2. Calculate the molarity of an acetic acid solution if 77.75 mL of the solution is needed to neutralize 131 mL of 1.12 M sodium hydroxide. The equation for the reaction is:

HC3H3O2(aq) + NaOH(aq) = Na+(aq) + C2H3O2-(aq) +H2O(aq)

3. Calculate the concentration of an aqueous KCl solution if 317 mL of the solution gives 38.4 g of AgCl when treated with excess AgNO3. The equation for the reaction is:

KCl(aq) + AgNO3(aq) = AgCl(s) +KNO3(aq)

4. Calculate the volume of 1.72M sulfuric acid that would be needed to neutralize 22.6 mL of a 3.15 M aqueous ammonia solution. The equation for the reaction is:

H2SO4(aq) + 2NH3(aq) = 2NH4+(aq) + SO4-2(aq)

Chemistry8 years ago### Chem help please me..?

1. _____________ is the direct conversion from the solid phase to the gas phase.

2. The heat of fusion of water is 335 J/g, the heat of vaporization of water is 2.26 kJ/g, the specifc heat of ice is 2.05 J/deg/g, the specific heat of steam is 2.08 J/deg/g and the specific heat of liquid water is 4.184 J/deg/g. How much heat would be needed to convert 10.57 g of ice at -7 °C to steam at 142 °C?

3. The heat of fusion of water is 335 J/g. How much heat would be required to melt 55.2 g of ice?

4. The heat of fusion of water is 335 J/g, the heat of vaporization of water is 2.26 kJ/g, and the specific heat of water is 4.184 J/deg/g. How many grams of ice at 0 ° could be converted to steam at 100 °C by 7,573 Joules of heat?

5. The heat of vaporization of water is 2.26 kJ/g. How much heat is needed to change 2.07 g of water to steam?

2 AnswersChemistry8 years ago### Heat questions.. Help!?

1. The heat of fusion of water is 335 J/g, the heat of vaporization of water is 2.26 kJ/g, the specific heat of ice is 2.05 J/deg/g, the specific heat of steam is 2.08 J/deg/g and the specific heat of liquid water is 4.184 J/deg/g. How much heat would be needed to convert 10.73 g of ice at -16 °C to steam at 149 °C?

2. The heat of fusion of water is 335 J/g. How much heat would be required to melt 37.3 g of ice?

3. The heat of fusion of water is 335 J/g, the heat of vaporization of water is 2.26 kJ/g, and the specific heat of water is 4.184 J/deg/g. How many grams of ice at 0 ° could be converted to steam at 100 °C by 9,519 Joules of heat?

2 AnswersChemistry8 years ago### Phase Changes... please help.?

1. The ____________ is the temperature and pressure at which all three phases can coexist.

2. The heat of vaporization of water is 2.26 kJ/g. How much heat is needed to change 3.74 g of water to steam?

3. The heat of fusion of water is 335 J/g, the heat of vaporization of water is 2.26 kJ/g, the specifc heat of ice is 2.05 J/deg/g, the specific heat of steam is 2.08 J/deg/g and the specific heat of liquid water is 4.184 J/deg/g. How much heat would be needed to convert 10.73 g of ice at -16 °C to steam at 149 °C?

4. The heat of fusion of water is 335 J/g. How much heat would be required to melt 37.3 g of ice?

5. The heat of fusion of water is 335 J/g, the heat of vaporization of water is 2.26 kJ/g, and the specific heat of water is 4.184 J/deg/g. How many grams of ice at 0 ° could be converted to steam at 100 °C by 9,519 Joules of heat?

1 AnswerChemistry8 years ago### gas stoiciometry chem help needed?

1. What volume of carbon dioxide gas (at STP) is produced when 2.08 moles of oxygen gas react completely in the following equation? 2CO + O2 = 2CO2

2. What volume of ammonia (at STP) is produced when 1.18 mole of hydrogen reacts completely in the following equation? N2 + 3H2 = 2NH3

3. What volume of ammonia (at STP) is produced when 1.17 mole of nitrogen reacts completely in the following equation? N2 + 3H2 = 2NH3

4. What volume of ammonia gas will be produced when 1.44 L of nitrogen react completely in the following equation? N2 + 3H2 = 2NH3

5. What mass of ammonia is produced when 3.08 L of nitrogen (at STP) react completely in the following equation? N2 + 3H2 = 2NH3

1 AnswerChemistry8 years ago### Gas Stoichiometry chemistry help needed?

1. What volume of carbon dioxide gas (at STP) is produced when 2.08 moles of oxygen gas react completely in the following equation?

2. What volume of ammonia (at STP) is produced when 1.18 mole of hydrogen reacts completely in the following equation?

3. What volume of ammonia (at STP) is produced when 1.17 mole of nitrogen reacts completely in the following equation?

4. What volume of ammonia gas will be produced when 1.44 L of nitrogen react completely in the following equation?

5. What mass of ammonia is produced when 3.08 L of nitrogen (at STP) react completely in the following equation?

2 AnswersChemistry8 years ago### Chem help needed- Dalton's Law Partial Pressure?

1. Calculate the partial pressure of helium in a 1.00 L flask that contains equal numbers of moles of He, Ne, and Ar at a total pressure of 8.35 atm.

2. We have a tank that contains O2 at 146 mmHg, N2 at 146 mmHg, and CO2 at 138 mmHg. We then add 135 mmHg of Ar. What is the pressure in the tank?

3. A 3.47 L flask is filled with carbon monoxide at 27 °C until the pressure is 9.71 atm. Calculate the total pressure after 2.37 moles of carbon dioxide has been added to the flask. (R=0.082 L-atm/K mol)

4. A tank contains Ar at 1.15 atm and Kr at 3.93 atm. We add enough Xe to give a total pressure of 8.97 atm. What is the partial pressure of the Xe?

5.Calculate the partial pressure of propane in a mixture that contains equal numbers of moles of propane (C3H8) and butane (C4H10) at 20 °C and 846 mmHg. (R=0.082 L-atm/K mol)

1 AnswerChemistry8 years ago### Chem help needed with Ideal?

1. Calculate the absolute temperature at which 55.4 g of O2 has a pressure of 1,850 mmHg in a 12.84 L container. (R=0.082 L-atm/K mol)

2. One mole of an ideal gas occupies 22.4 L at standard temperature and pressure. What would be the volume of one mole of an ideal gas at 208 °C and 1,476 mmHg. (R=0.082 L-atm/K mol)

3. Calculate the pressure in atmospheres of 28.7 g of CO2 in a 8.57 L container at 195 °C. (R=0.082 L-atm/K mol)

4. 8.94 g of an unknown gas occupies 1.58 L at 40 °C and 1.47 atm. What is the molecular mass of the unknown gas? (R=0.082 l-atm/K mol)

5. Calculate the volume in liters of a 5.44 mol sample of a gas at 228 °C and 4.37 atm. (R=0.082 L-atm/K mol)

1 AnswerChemistry8 years ago### Needing help with chem problems Mole-Mass-Volume?

1. If we have a gas with a formula mass of 85.7, what is the density of the gas at STP?

2. If we have 38.99 L of a gas at STP, how many moles of that gas do we have

3. If we have 98.1 L of a gas at STP with a mass of 56.7 g, what is the formula mass of the gas

4. If we have 3.43 moles of a gas at STP, how much volume will it occupy

5. One mole of an ideal gas at STP will occupy a volume of _____ L

4 AnswersChemistry8 years ago### Need help with chem problems with Avadadro's Law.?

1. If 1.77 moles of a gas occupies 3.31 L at a particular temperature and pressure, how many moles of gas have to be added to give a volume of 5.86 L?

** my answer: 3.13 moles

2. 3.64 moles of gas occupies 1.86 L at a given tempererature and pressure. If we add 6.06 moles of gas what will be the new volume?

** my answer: 3.1 L

3. If 2.14 moles of a gas occupies 3.14 L at a particular temperature and pressure, how many moles of gas will be needed to give a volume of 5.96 L?

** my answer; 4.06 moles

4. 1.29 moles of gas occupies 2.56 L at a given tempererature and pressure. If we increase the number of moles of gas to 7.62 what will be the new volume?

** my answer: 15.12 L

5. To increase the volume of a sample of gas while holding the pressure and temperature constant, we must ____________ the number of moles of gas.

******** I have taken the questions before and seem to not be able to get the correct answer. I thought Avagadro's Law was V1/n1 = V2/n2 *************

1 AnswerChemistry8 years ago### Combined Gas laws help needed?

1. A sample of xenon occupies a volume of 788 mL at 5.99 atm and 49 °C. If the volume is changed to 500 mL and the temperature is changed to 60 °C, what will be the new pressure?

2. A sample of neon occupies 3.22 L at 5.22 atm and 19 °C. What will be the volume at 2.23 atm and 61 °C?

3. A sample of nitrogen has a volume of 2.34 L at 996 mmHg and 87 °C. What volume will it occupy at standard temperature and pressure?

4. A sample of gas occupies 8.23 L. If the pressure is increased 16 times and the absolute temperature is increased 8 times, what will be the new volume?

5. A sample of argon occupies 454 mL at 1.95 atm and 216 °C. If the volume is changed to 408 mL and the temperature is changed to 229 °C, what will be the new pressure?

2 AnswersChemistry8 years ago### Boyle's Law help..?

1. What would be the volume of a balloon filled with 6.17 L of H2 gas collected at 1,282 mm Hg if the pressure were increased to 2,452 mm Hg?

2. Calculate the volume of a balloon that could be filled at 1.00 atm with the helium in a 21.1 L gas cylinder in which the pressure is 13.8 atm (assume no temperature change).

3. A 939 mL sample of Ar gas was collected at 1,424 mm Hg. What would be the pressure in mm Hg if the gas were allowed to expand o 2,409 mL at constant temperature.

4. A sample of nitrogen at 20.0 degrees C has a volume of 443 mL at a pressure of 697 mm Hg. To change the volume to 1,807 mL, what must be the new pressure?

5. If we want to compress a gas to one-half of its orginial volume without changing the temperature, we will need to _____ the pressure.

1 AnswerChemistry8 years ago### Kinetic Theory, please help.?

1. If the molecules in a Sample of gas are given higher average velocities in a container of fixed volume, _____ increases.

2. The pressure from a gas results from _____ of the rapidly moving gas molecules with the wall of the container.

3. An ideal gas consists of a large number of extremely tiny particles in chaotic, _____ motion.

4. In an ideal gas, the particles lose no energy when they ______.

5. If we ____ the volume of a container at constant temperature we will increase the rate at which the molecules hit the walls of the container resulting in an increase in pressure.

2 AnswersChemistry8 years ago### Lewis Structure.... help...?

1. The element S will normally form _____ covalent bonds

2. To have more than 8 electrons around an atom in a Lewis structure the element must be in at least the ________ row of the periodic table

3. Which of the following violates the octet rule:

A. BH3

B. CH4

C. NH3

D. H2O

E. HF

4. Which of the following contains a triple bond:

A. HCl

B. N2

C. C2H4

D. NH3

E. CH4

5. The number of valence electrons in the H3PO4 molecule is ______

1 AnswerChemistry8 years ago### Lewis Atoms.. formulas.?

1. How many electroms does the Na+ ion have in the outer level?

2. What formula would you predict for a binary ionic compound of barium and chlorine?

3. What formulas would you predict for a bionary ionic compound of sodium and nitrogen?

4. What ionic charge would you think most likely for the element Ba?

5. Ion in a crystal arrange themselces in such a way as to _____ the distance between cations and the nearest anions.

1 AnswerChemistry8 years ago### helppppp!!!! Periodic Trends!!!?

1. Which of the following has the largest radius?

a- Ge

b- Kr

c- Sc

d- Se

2. Which of the following has the larges radius?

a- Ag

b- Au

c- Cu

d- Mg

3. Which of the following has the largest radius?

a- Br

b- Cl

c- F

d- I

4. ____ is a measure of the energy needed to remove one electrom from the valence shell of an atom.

5. The elements on the left side of the periodic table are ______.

1 AnswerChemistry8 years ago### Theoretical Yield. Help.?

1. The __ is the mass of product that should be formed in a chemical reaction according to the stoichiometry of the balanced reaction.

2. How many grams of Ca3N2 can be formed from 7.36 g of calcium and 1.96 g of nitrogen in the following reaction 3Ca + N2 = Ca3N2

3. How many grams of SO3 can be formed from 18.82 g of SO2 and 3.05 g of O2 in the following reaction 2SO2 + O2 = 2SO3

4. How many moles of P4S10 could be formed from 3.48 moles of P4 and 5.73 moles of S8 in the following reaction 4P4 + 5S8 = 4P4S10

5. How many moles of NO2 could be formed from 15.63 moles of NO and 3.71 moles of O2 in the following reaction 2NO + O2 = 2NO2

1 AnswerChemistry8 years ago### How many grams of SO3 can be found from 10.71 g of SO2 and 1.04 g of O2 in 2SO2 + O2 = 2SO3?

How many grams of SO3 can be found from 10.71 g of SO2 and 1.04 g of O2 in the reaction

2SO2 + O2 = 2SO3

1 AnswerChemistry8 years ago### Please Someone help me.. Stoiciometry!!?

How many moles of CO would be needed to reduce 39.8 grams of iron(III) oxide if the equation for the reaction is Fe2O3 + 3CO = 2Fe + 3CO2

How many moles of NaCl are needed if we want to make 49.68 grams of PbCl2 by the reaction

2NaCl + Pb(NO3)2 = PbCl2 + 2NaNO3

How many grams of NaCl are needed if we want to make 6.275 moles of AgCl by the reaction

NaCl + AgNO3 = AgCl + NaNO3

How many grams of MnO2 are needed if we want to make 0.7249 moles of O2 by the reaction

3MnO2 = Mn3O4 + O2

How many grams of KNO3 will be produced if we produce 24.38 grams of Ni(OH)2 in the reaction

Ni(NO3)2 + KOH = 2KNO3 + Ni(OH)2

How many grams of H2 are needed if we want to make 98.26 grams of NH3 by the reaction

N2 + 3H2 = 2NH3

1 AnswerChemistry8 years ago