Tuesday

January 17, 2017
Total # Posts: 3,280

**Calc**

How do you do the derivative of an inverse trig function? arcsin (sqrt2/2)??

*October 26, 2011*

**Chemistry**

yes thank you i understand the parts for moles of KHP and NaOH. So the mw of KHP was given to me which was 204.44g/mol so for moles of KHP i did 1/204.44 and got 0.004 and then for NaOH i got 0.004 as well. Then for the concentration of NaOH would i do 0.004/0.0145 and 0.004/0...

*October 26, 2011*

**Chemistry**

For a chemistry lab the experiment was to carry out an acid-base titration to determine the exact concentration of a sodium hydroxide solution. Two trials were completed and the data collected was: mass of weighing paper, mass of weighing paper + KHP, mass of KHP, initial ...

*October 26, 2011*

**Chemistry(Please help, thank you!!)**

Thank you!!

*October 25, 2011*

**Chemistry(Please help, thank you!!)**

ok i do not understand at all but thank you for your help.

*October 25, 2011*

**Chemistry(Please help, thank you!!)**

SO would it be 27.80 / 10.00?

*October 25, 2011*

**Chemistry(Please help, thank you!!)**

Determine the concentration of a NaOH solution if 27.80mL of NaOH is required to neutralize 10.00mL of a 1.00 M H2SO4 solution. (Hint:Review monoprotic vs. diprotic acids.) would I do (27.80)(10)? Thank you for your help!!

*October 25, 2011*

**Chemistry(Please help, thank you!)**

ok so for mole of kHP it would be 1/204.44 = 0.00489 g/mol? The volume of NaOH for trial 1 was 14.50 mL and for trial 2 it was 9.90mL. So would it be 39.998 which is molecular mass of NaOH divided by the volume?

*October 24, 2011*

**Chemistry(Please help, thank you!)**

For a chemistry lab the experiment was to carry out an acid-base titration to determine the exact concentration of a sodium hydroxide solution. Two trials were completed and the data collected was: mass of weighing paper, mass of weighing paper + KHP, mass of KHP, initial ...

*October 24, 2011*

**Geology**

For my final I am to write a paper discussing the following : Select some product produced in your city or state that is made from earth, mineral, or energy resources. One example would be the tar paper used as a building material. (Do not use this example). Prepare a 700- to ...

*October 23, 2011*

**Chemistry**

Thank You!!!

*October 23, 2011*

**Chemistry**

A concept map was to be created on acids and bases. The concept terms that were given to use were: aqueous solution,bases,acids,ions,weak bases, strong bases, strong acids, weak acids,dissociation, weak electrolyte, strong electrolyte,reaction,salt, neutralization, hydronium ...

*October 23, 2011*

**Chemistry(Please help!!)**

For a chemistry lab the experiment was to carry out an acid-base titration to determine the exact concentration of a sodium hydroxide solution. Two trials were completed and the data collected was: mass of weighing paper, mass of weighing paper + KHP, mass of KHP, initial ...

*October 23, 2011*

**Science- physics**

Thank you so much! My teacher has NO idea how to teach us anything! I really appreciate your help! Thanks <3

*October 23, 2011*

**Science- physics**

How much does a 20ft x 10ft x 8ft swimming pool filled with water weight? Assume the water has a weight density of 62 lbs/ft3. I know the answer is 99,200 pounds but how do I get that answer? Thanks<3

*October 23, 2011*

**Science- physics**

An aluminum bar weighs 17 pounds in air. How much force is required to lift the bar while it is immersed in gasoline? The weight of aluminum is 170 pounds/ft3 and that of gasoline is 42 pounds/ft3. I know that the answer is 12.8 pounds but how do I get to that answer? Thanks<3

*October 23, 2011*

**Science- physics**

An iron anchor weighs 250 pounds in air and has a weight density of 480 lbs/ft3. If it is immersed in sea water that has a weight density of 64 lbs/ft3, how much force would be required to lift it while immersed? I know the answer is 217 pounds but I need help on trying to get...

*October 23, 2011*

**Science- physics**

A balloon weighing 80 kg has a capacity of 1200 m3. If it is filled with helium, how great a payload can it support? The density of helium is 0.18 kg/m3 and the density of air is 1.30 kg/m3. Express your answer in Newtons. I know the answer is 12, 400 Newtons I just don't ...

*October 23, 2011*

**Science**

The formula for density is... density= mass/volume So yes you would divide 6773 g/500 mL!

*October 23, 2011*

**Chemistry**

For my first trial KHP was 1.00g and for the second trial it was the same. So to find moles of KHP would I do 204.44g/mol X 1/1g which would be 204.44g/mol?

*October 23, 2011*

**Chemistry**

For a chemistry lab the experiment was to carry out an acid-base titration to determine the exact concentration of a sodium hydroxide solution. Two trials were completed and the data collected was: mass of weighing paper, mass of weighing paper + KHP, mass of KHP, initial ...

*October 23, 2011*

**Chemistry**

Write a net ionic equation for the overall reaction that occurs when aqueous solutions of potassium hydroxide and carbonic acid are combined. KOH + H2CO3 = KCO3 + H30 K^+(aq) + OH^-(aq) + h2CO3 (aq) = K^+(aq) + CO3^2+(aq) + H3O(aq) Is this correct so far?

*October 22, 2011*

**science**

If a scientist changes two variable he/she would not know which change would increase or decrease his/her theory or hypothesis. The scientist wants to determine one thing that changed it the most not two things!

*October 20, 2011*

**Ap chem**

When .4000 g of CH4 is burned in excess oxygen in a bomb calorimeter that has a heat capacity of 324, the temperature increases 6.795 degrees celsius. How much energy is released? (in kJ/mol CH4)

*October 20, 2011*

**Science**

A container with equal sides of 8 cm is filled with 1200g of fluid. What is the force in Newtons on the bottom of the container?

*October 20, 2011*

**math**

a rectangle has an area of 330m^2 , one side is 7 m longer than the other what are the dimensions of this rectangle

*October 20, 2011*

**Math**

Simplify a)(1-ã3)(2+ã6)(5+ã2) b) -5ã45+ã52+3ã125

*October 19, 2011*

**5th grade math**

seventy five multiplied by one hundred twenty

*October 19, 2011*

**science**

how long does a teenager need to sleep at night?? my teacher asked this question and if you get it right, you get 2 extra points on a test, so please help me!!

*October 17, 2011*

**Physical Education**

P.E. is a time to achieve physical activity. To obtain a healthy living style you should exercise for 60 min a day. Most kids/teenagers would probably not chose to do that therefore schools decided to include that needed exercise in the kids' school time.

*October 17, 2011*

**Spanish**

I'm in the 8th grade and I have been taking French now for about a 1 1/2. I have learned many things and it is probably the easiest way to learn about another country! salut! (thats goodbye in french btw)

*October 15, 2011*

**Chemistry**

The empirical formula for Brilliant Blie dye is C37 H34 N2 O9 S3 Na2, and the formula weight is 792.86 g/mol. How would you prepare a 4.73 X 10^-6 M solution of Brilliant Blue dye? How many grams of the dye do you need to add to a 1.00 L of water to make this solution? I have ...

*October 12, 2011*

**Chemistry**

To calculate the percent error you would use the error in measurement divided by accepted value times 100 correct? So for an experiment in which you had to find the concentration of a dye in a powdered drink solution, to find the percent error would you use the number you ...

*October 12, 2011*

**Chemistry**

A sample of 30.0 mL of sulfuric acid solution was titrated with 0.720 M KOH. It was found that 46.9 mL of the base was needed to neutralize the acid. What is [H2SO4]? would you do (30.0)(0.720) / 46.9 ?

*October 12, 2011*

**Chemistry**

What volume of o.410 M HNO3 would you need to neutralize 18.75mL of 0.376M Ba(OH)2? Would you do (0.410)(18.75) / 0.376? Or (0.410)(0.376) / 18.75

*October 11, 2011*

**Chemistry**

Oh ok thank you!

*October 11, 2011*

**Chemistry**

If 7 mL of water is added to 3 mL of a 0.50 M KOH solution, the concentration of KOH is changed to? I am not sure how to go about doing this. Please help, thank you!!! Would I do (7)(3) / 0.50?

*October 11, 2011*

**Chemistry**

so would it be Mg3N2 + H2O -> 2MgOH + NH3

*October 9, 2011*

**Chemistry**

Write the balanced equation for: Magnesium nitride + water -> magnesium hydroxide + ammonia MgNO2 + H2O -> MgOH + NH3 Is this correct?

*October 9, 2011*

**Chemistry**

thank you!

*October 9, 2011*

**Chemistry**

Would this be correct for the complete equation? Ba^2+ + OH^- + H^+ + Br^- = Ba^2+ + Br^- + H2O

*October 9, 2011*

**Chemistry**

Write the net ionic equation for the reaction that occurs when aqueous solutions of barium hydroxide and hydrobromic acid are combined. I know that the first part of the formula would be BaOH + HBr but I do not know what the product would be since HBr is one thing. I do not ...

*October 9, 2011*

**Language**

What do these sets of words have in common?(Hint: Look for a sound, a keyboard, or the way they are written.) BCDEGPV QWERTYUIOP ij

*October 6, 2011*

**Language**

What do these sets of words have in common?(Hint: Look for a sound, a keyboard, or the way they are written.) BCDEGPV QWERTYUIOP ij

*October 6, 2011*

**english**

Where is pride and prejudice does mr. bennet confess that he married mrs. bennet because of her looks? a volume and chapter would be great:) I know the page numbers will be different in eat edition.

*October 6, 2011*

**algebra**

If you enter Interstate 40 at mile marker 23 in Sayre, Oklahoma, how far would you need to travel to reach mile marker 125 in El Reno, Oklahoma? After reaching El Reno, you might worry that your vehicle is running low on fuel. You know that your vehicle can travel 32 miles per...

*October 5, 2011*

**Chemistry**

is L the volume?

*October 5, 2011*

**Chemistry**

when doing a lab experiment on limiting reagents for CoCl2 there is a chart to fill out that says to find the concentration of test tubes 1-6, find the volume delivered and find the moles of CoCl2. How would I find the moles of CoCl2 for each test tube?

*October 5, 2011*

**Chemistry(please check, thank you!!)**

Thank you!

*October 5, 2011*

**Chemistry(please check, thank you!!)**

Is this equation balanced? CoCl2(aq) + Na2CO3(aq) -> CoCO3(s) + 2NaCl(aq) I think that it is because there is 1 Co on the left and 1 on the right. There is 2 cl on the left and 2 on the right. 2 Na on the left and 2 on the right and 3 CO on left and on right. Am I correct...

*October 5, 2011*

**history**

When were hunter gatherers around in america? why and when(a date or range would be great) did they settle down?

*October 5, 2011*

**geometry**

THANK YOU TCHRWILL

*October 3, 2011*

**Chemistry, Need Help!!**

a)How many grams of H2 are needed to produce 14.27 g of NH3? b)How many molecules (not moles) of NH3 are produced from 1.57×10−4 g of H2 ?

*October 3, 2011*

**Chemistry**

A)What mass of carbon dioxide is produced from the complete combustion of 7.00×10−3 g of methane? B)What mass of oxygen is needed for the complete combustion of 7.00×10−3 g of methane?

*October 3, 2011*

**calculus**

Let f(x)=6x+16x^2 . Then the equation of the tangent line to the graph of f(x) at the point (2,16) is given by y=mx+b for m= and b=

*October 2, 2011*

**Chemistry**

If the standard state of sufur is S8 (s), which of the following equations represents the standard enthalpy of formation of H2SO4 (ℓ) ? A. 2H (g) + S (g) + 4 O (g) H2SO4 (ℓ) B. H2 (g) + S8 (g) + 2 O2 (g) H2SO4(ℓ) C. H2SO4 (ℓ) &#...

*October 2, 2011*

**Chemistry**

Calculate the enthalpy change, ΔrH, for the following reaction, 4 NH3 (g) + 5 O2(g) → 4 NO (g) + 6 H2O (g) given the thermochemical equations below. N2 (g) + O2 (g) → 2 NO (g) ΔrH° = +181 kJ N2 (g) + 3 H2 (g) → 2 NH3 (g) ΔrH° = ...

*October 2, 2011*

**Chemistry**

If H for the reaction I2 (s) 2I (g) is 153 kJ/mol. What is the longest wavelength of light that can break an I – I bond? In other words, what is the minimum energy, expressed in terms of wavelength, required to break one I – I bond? A. 246 nm B. 465...

*October 2, 2011*

**Chemistry(Please check)**

What is the oxidation number of chromium in K2Cr2O7 so k=+1 (2) = 2 O=-2(7) = -14 2x + 1 +(-14) = 0 2x-12=0 x=6 so Cr is 6 Is this correct?? Thank you!!

*October 1, 2011*

**math**

are we allowed to use calculators in sat 1 math?

*September 30, 2011*

**math**

A rectangle was constructed using 24 square tiles. If you add the length and width of her rectangle together, you would get 11. What is the length and width of this rectangle?

*September 29, 2011*

**Chemistry**

What is the oxidation number of chromium in K2Cr2O7? I know that K = 1 O=-2 so 7*-2=-14 I do not know what to do now. Thank you for your help!

*September 27, 2011*

**7th grade math**

it is a grid 0,5.10.15,20 through 55 then it cost a camp;er 25.00 how does this work??

*September 26, 2011*

**7th grade math**

i need help with variables and patterns algebra

*September 26, 2011*

**Chemistry(Please help, thank you!!)**

Thank you. I understand how you got the numbers for Na and H and the -6 for O but why does S have to be +4?

*September 26, 2011*

**Chemistry(Please help, thank you!!)**

What is the oxidation number of sulfur (s) in NaHSO3? I know that Na is 1 but I do not know what else to do. Please explain, thank you for your help!!

*September 26, 2011*

**Chemistry**

When aqueous CuSO4 is added to aqueous Na2S2O3, why is there no reaction?

*September 25, 2011*

**Physics**

Can you explain how to figure this out? A helicoptor accelerates at a rate of 2m/s^2. If you drop a rock out of the helicoptor 3 seconds after takeoff how high is the helicoptor when the rock hits the ground. Thanks

*September 25, 2011*

**physics**

Two particles are at the same point at the same time, moving in the same direction. Par- ticle A has an initial velocity of 9 m/s and an acceleration of 2.7 m/s2. Particle B has an initial velocity of 2.9 m/s and an acceleration of 4.2 m/s2. At what time will B pass A? Answer ...

*September 25, 2011*

**Chemistry(Please help, thank you!!!)**

Write the balanced, complete, and net ionic equations for each precipitation reaction. 1) AgNO_3 + CoCl_2 ---> BE: AgNO_3(aq) + CoCl_2(aq) ---> AgCl_2 (aq) + Co(NO_3)(aq) CIE: Since the balanced equation is all (aq) there is no reaction so no complete or net equation. 2...

*September 24, 2011*

**Chemistry(Please check!!)**

Write the balanced, complete, and net ionic equations for each precipitation reaction. 1) AgNO_3 + CoCl_2 ---> BE: AgNO_3(aq) + CoCl_2(aq) ---> AgCl_2 (aq) + Co(NO_3)(aq) CIE: Since the balanced equation is all (aq) there is no reaction so no complete or net equation. 2...

*September 24, 2011*

**physics**

A student, starting from rest, slides down a water slide. On the way down, a kinetic frictional force (a nonconservative force) acts on her. The student has a mass of 75 kg, and the height of the water slide is 11.1 m. If the kinetic frictional force does -6.8 × 103 J of...

*September 21, 2011*

**Physics**

A 49.5-g golf ball is driven from the tee with an initial speed of 41.9 m/s and rises to a height of 29.7 m. (a) Neglect air resistance and determine the kinetic energy of the ball at its highest point. (b) What is its speed when it is 5.66 m below its highest point?

*September 21, 2011*

**Physics**

A 27-kg girl is bouncing on a trampoline. During a certain interval after leaving the surface of the trampoline, her kinetic energy decreases to 150 J from 430 J. How high does she rise during this interval? Neglect air resistance.

*September 21, 2011*

**Physics**

Starting from rest, a 1.7x10-4 kg flea springs straight upward. While the flea is pushing off from the ground, the ground exerts an average upward force of 0.44 N on it. This force does 2.4x10-4 J of work on the flea. (a) What is the flea's speed when it leaves the ground...

*September 21, 2011*

**Physics**

A person pushes a 23.4-kg shopping cart at a constant velocity for a distance of 31.1 m on a flat horizontal surface. She pushes in a direction 34.8 ° below the horizontal. A 38.5-N frictional force opposes the motion of the cart. (a) What is the magnitude of the force ...

*September 21, 2011*

**Math(Please help, very confused!)**

A piece of copper contains 3.6 x 10^8 atoms. What is the volume of the sample in units of liters? i have no idea how to start this. Please help thank you!!!

*September 20, 2011*

**Calculus**

2sin(2theta) + sqrt(3) = 0 interval (0,2pi) How do I solve this? I thought about maybe subtracting the sqrt(3) from both sides, so that i would have 2sin(2theta) = -sqrt(3) Then maybe dividing by two? sin(2theta) = -sqrt(3)/2 Am I doing anything right here? It's been a ...

*September 20, 2011*

**chemistry**

If you dissolve 29.25 g of sodium chloride in 250 g of H2O. What would be the freezing point? Kfp- -1.86 degrees C/molal I know the formula is K times molality. I am taking -1.86(2.00) and getting -3.72 degrees Celsius, when the answer is -7.44 degrees. What am I doing wrong?

*September 19, 2011*

**Science**

Unscramble acnsrl spgei

*September 19, 2011*

**Math(Please help!!!)**

A piece of copper contains 3.6 x 10^8 atoms. What is the volume of the sample in units of liters? I know that first you have to get atoms to cancel out but them I do not know what to do!

*September 18, 2011*

**physics**

A 0.07 kg toy is made up of a spring of constant 375 N/m. When you place the toy on the floor, cock the spring 7 cm and release it, the toy jumps upwards. What is in Joules the mechanical energy of the toy when sitting on the floor with a cocked spring? Use 10 m/s2 for g.

*September 16, 2011*

**physics**

A 0.05 kg toy is made up of a spring of constant 466 N/m. When you place the toy on the floor, cock the spring 5 cm and release it, the toy jumps upwards. What is in Joules the spring potential energy stored in the toy when sitting on the floor with a cocked spring? Use 10 m/...

*September 16, 2011*

**physics**

A 0.05 kg toy is made up of a spring of constant 466 N/m. When you place the toy on the floor, cock the spring 5 cm and release it, the toy jumps upwards. What is in Joules the spring potential energy stored in the toy when sitting on the floor with a cocked spring? Use 10 m/...

*September 16, 2011*

**physics**

It takes 9.10 J of work to stretch a spring 5.10 cm from its unstressed length. What is the spring constant k in N/m?

*September 16, 2011*

**physics**

It takes 5.50 J of work to stretch a spring 5.90 cm from its unstressed length. What is the spring constant k in N/m?

*September 16, 2011*

**physics**

Amy threw a ball of mass m=0.79 kg horizontally with an initial velocity v=33.4 m/s from a height h=1.9 m. What is the kinetic energy of the ball just before it touches the ground? Express your answer in Joules and use 10 m/s2 for g.

*September 16, 2011*

**physics**

A 0.730 kg particle has a speed of 3.00 m/s at point A and kinetic energy of 7.40 J at B. What is its speed at B? Answer in units of m/s.

*September 16, 2011*

**physics**

A 4.62 x 10-5 kg raindrop falls vertically at constant speed under the influence of gravity and air resistance. After the drop has fallen 83.7 m, what is the work done by gravity? Answer in units of milliJoule (a thousandth of a Joule) and use 9.8 m/s2 for g

*September 16, 2011*

**Math(Please help)**

A piece of copper contains 3.6 x 10^8 atoms. What is the volume of the sample in units of liters? I know that first you have to get atoms to cancel out but them I do not know what to do.

*September 13, 2011*

**Math(Please help! Thank you!!)**

A piece of copper contains 3.6 x 10^8 atoms. What is the volume of the sample in units of liters? I know that first you have to get atoms to cancel out but them I do not know what to do.

*September 13, 2011*

**scientific method and measurement 8th Hons science**

You see i already know its not replicable or such 13 letters long and it ends with an N.

*September 12, 2011*

**scientific method and measurement 8th Hons science**

Can Anyone Please Help Me?

*September 12, 2011*

**scientific method and measurement 8th Hons science**

what allows results to be verified to maintain credibility?

*September 12, 2011*

**Math(Please help)**

The radius of a niobium atom is 131 pm. How many niobium atoms would have to be laid side by side to span a distance of 1.4 mm?? I know that 10^9 is pm or is it -9??

*September 11, 2011*

**Math**

4.47 x 10^1 g How wouldI convert this to nanmograms? would I use 1mg / 10^-9 g? I do not understand how to do this

*September 11, 2011*

**math**

8 decimeters

*September 11, 2011*

**Math(Please check! Thank you!!)**

metric system conversions 1)3.68kg = ? g (3.68 kg) (10^-3 / 1kg) = 3.68 x 10^-2 g 2) 568cm = ? m (568cm) (1 m /100cm) = 5.68 m Are these correct?

*September 11, 2011*

**PHYSICS**

A student of weight 830 N was sent to another planet called Nerdland. If Nerdland has a mass that is three times the mass of the earth and a radius that is half the radius of the earth, what would be the mass in kg of the student when on Nerdland?

*September 8, 2011*

**Calculus**

find f(3) and f'(3), assuming that the tangent line to y=f(x) at a=3 has the equation y=5x+2.

*September 7, 2011*