Wednesday

February 22, 2017
Total # Posts: 689

**Math**

(# of dimes)/(total # of coins)

*January 8, 2013*

**chemistry-opps again**

^I meant molar mass of 4* carbons, because there are actually 4 carbons in Sn(CH3CO2)2 Sorry about that.

*January 8, 2013*

**chemistry - opps**

^I meant molar mass of 3* carbons, because there are actually 3 carbons in Sn(CH3CO2)2

*January 8, 2013*

**chemistry**

First, determine how much of the 325g is carbon. 324g [(molar mass of 2 carbon)/(molar mass of Sn(CH3CO2)2)] Then, convert grams of C to mole by dividing by C's molar mass. Finally, convert the mole to atoms. You know for every one mole there is 6.022 × 10^23 atoms.

*January 8, 2013*

**algebra**

http://www.purplemath.com/modules/systlin4.htm

*January 8, 2013*

**Math**

Standard from should be in this format: Ax +By= C http://www.algebra-class.com/writing-equations-2.html

*January 8, 2013*

**algebra 2**

For the first three, you would have to apply the rational zero theorem ((Broken Link Removed) and then use synthetic division ((Broken Link Removed) to see if the remainder is zero. For the last two, you would group the terms and factor out a common factor method(http://www....

*December 31, 2012*

**Help Math**

incorrect. Law of addition: P(A or B) = P(A)+ P(B)- P(A and B) source: http://www.quickmba.com/stats/probability/

*December 30, 2012*

**chemistry**

this link should help you answer your question: http://www.titrations.info/titration-errors

*December 28, 2012*

**Urgent!**

how to find mean, median, mode, and range: http://www.purplemath.com/modules/meanmode.htm

*December 27, 2012*

**science**

momentum = (mass)*(velocity)

*December 20, 2012*

**science**

If the amino acid is changed, the tertiary structure (interaction between R groups) will be changed. As a result, the protein's structure(/folding) and therefore function will be different.

*December 18, 2012*

**Biology**

http://utminers.utep.edu/rwebb/html/what_is_a_mutation_.html

*December 18, 2012*

**Biology**

either source: http://en.wikipedia.org/wiki/Mutation

*December 18, 2012*

**Biology**

http://staff.tuhsd.k12.az.us/gfoster/standard/bmut.htm

*December 18, 2012*

**Chemistry**

Every 14 seconds, the isotope's mass is halved.

*December 12, 2012*

**chemistry**

http://scienceworld.wolfram.com/biography/Dalton.html

*November 19, 2012*

**Chemistry**

PV=nRT where P= pressure in atm V= volume in L n =(mass of Ar)/(molar mass of Ar) R=0.082058 L atm mol-1 K-1 T= temperature in Kelvins

*November 9, 2012*

**Chem**

what are the units? http://www.jiskha.com/display.cgi?id=1352484673

*November 9, 2012*

**Chem**

Convert the path length to cm. Plug in Beer's law equation and solve for c. A = ε l c http://www.chm.davidson.edu/vce/spectrophotometry/beerslaw.html

*November 9, 2012*

**Chemistry**

volume = (length)*(width)*(height) density= mass/ volume

*September 29, 2012*

**chemistry**

opps yes your formula is correct!

*September 9, 2012*

**chemistry**

The correct formula: q = mcΔT or c = q/[(m)(ΔT)] http://chemistry.about.com/od/workedchemistryproblems/a/Specific-Heat-Example-Problem.htm

*September 9, 2012*

**CHEMISTRY**

This link is helpful: http://chemistry.csudh.edu/faculty/noel/CHE317L/Extraction%20Experiment.htm read up to X = 8.0 grams of A extracted into the ether. For your question, you would subtract x from 9.81g after you solve for x.

*September 9, 2012*

**chemistry**

volume of sphere = 4/3 π r^3 density = mass/volume

*September 8, 2012*

**chemistry**

1)look at the units. see how this cancels out to give you columb, the SI unit of quantity of electric charge (columb/sec)*(sec) = ? columb 2) divide ? columb by charge on an electron

*September 8, 2012*

**Chemistry**

molality = moles of solute/kilograms of solvent notice how the units cancel out to moles of solute: (moles of solute/kg of solvent)*(kg)= moles of solute

*September 8, 2012*

**Biology**

Molarity (M) = mol / liter = moles/ 1000ml Therefore, 0.8M = 0.8 mol/ 1000 ml Know that the units cancel out to mol: (0.8 mol/1000 ml)*(150ml) = ? mol if you multipy ? mol by the molar mass of NaCl , you would end up with grams of NaCl (? mol)*(__ g/ mol)= ___g NaCl

*September 8, 2012*

**Chemistry**

http://www.jiskha.com/display.cgi?id=1347138502

*September 8, 2012*

**chemistry**

Read Freezing Point Depression Section: http://www.chemistryexplained.com/Ce-Co/Colligative-Properties.html

*September 8, 2012*

**Geometry**

Angle A is 30 more than twice angle B can be written as A = 2B + 30 Because we know that angle A and angle B form a linear pair, we know that A + B = 180 Plug the first equation into the second equation and solve for A. Once you solve for A, plug the know A value into into ...

*September 8, 2012*

**chemistry**

2S + 3O2 -> 2SO3 This example should help you. http://www.chem.tamu.edu/class/majors/tutorialnotefiles/limiting.htm

*September 4, 2012*

**chemistry**

1)Convert 25* Celsius to Kelvin. Celsius + 273.15 = Kelvin Plug the given numbers in this formula and solve for final temperature. q = mcΔT where q = heat energy m = mass c = specific heat ΔT = change in temperature = final temperature - initial temperature

*September 2, 2012*

**MATHS**

Hint: Two opposite angles of a parallelogram are congruent, meaning they are equal.

*June 29, 2012*

**geometry**

volume = length x weight x height the ends of the box are square, so height = weight volume = length x height x height plug in the numbers and solve for height

*June 29, 2012*

**maths**

If 3/5 of the students (you can also think this as 3 out of 5 students) are girls, how many of the 5 students are boys? Present in fraction form. This is the simplified or reduced fraction. fraction = part/whole = number of boys/ number of students Set the reduced fraction = ...

*June 29, 2012*

**Science**

http://www.biologyjunction.com/taxonomy_notes_bi.htm

*May 9, 2012*

**Science**

Here's the chemical equation, but you need to balance it still: CuCl2 + NaNO3 => Cu(NO3)2 + NaCl The reactant that produces the lesser amount of product is the limiting reagent. Here's an example problem: http://www.chem.tamu.edu/class/majors/tutorialnotefiles/...

*May 9, 2012*

**statistics**

https://statistics.laerd.com/statistical-guides/standard-score-3.php

*May 9, 2012*

**chemistry**

Independent variable goes on the x-axis, and the dependent variable goes on the y-axis.

*May 9, 2012*

**Genral Chemistry**

http://chemistry.about.com/od/workedchemistryproblems/a/phstrongbase.htm This example should help you with your question.

*April 17, 2012*

**Chemistry**

To convert from .95 mol Al to mol H, you would use the coefficients in the balanced equation. Here's an example of a stoichiometry problem: http://www.jiskha.com/science/chemistry/stoichiometry.html

*March 9, 2012*

**Chemistry**

The maximum number of moles of AgCl that could be obtained would be the number of moles of AgCl produced by the limiting reagent.

*March 9, 2012*

**geometry**

ball = sphere Find the surface area of a sphere. A = 4*pi*(radius)^2 source: http://math.about.com/od/formulas/ss/surfaceareavol.htm

*March 8, 2012*

**Chemistry**

1) impure anything should be depressed and/or broad compared to literature melting range 2) pure anything should be at the literature melting range

*March 8, 2012*

**Chemistry**

Here are the rules for counting significant figures: http://academic.umf.maine.edu/magri/PUBLIC.acd/tools/SigFigsAndRounding.html

*March 8, 2012*

**Chemistry**

a)% recovery = [final mass/ initial mass] x 100% b) hint: think about the state of matter of the impurities

*March 8, 2012*

**physics**

See example 2: http://www.cliffsnotes.com/study_guide/Dynamics.topicArticleId-10453,articleId-10417.html

*January 4, 2012*

**7th Grade Math**

Distance= rate*time Distance upstream = distance downstream Time should be converted to hour b/c the units for rate is in /hour. We know the total time so assign one of the times x (upstream time b/c you would only have to solve for x to get its time) and the other the total ...

*January 4, 2012*

**science**

Density = mass/ volume

*December 20, 2011*

**math**

plug in n for 15 15+(-12) which is the same thing as: 15-12 = ?

*December 20, 2011*

**chem**

Find the molecular weight of AgCl2. That's grams/ 1 mol AgCl2. To convert: (3.6 mol AgCl2)(___g/ 1 mol AgCl2) Notice how the mol unit cancels out and you're only left with the desired grams unit.

*December 15, 2011*

**chemistry**

PV=nRT Solve for V. Here's a sample problem: http://faculty.clintoncc.suny.edu/faculty/Mike.Lawliss/My_webpage/map/pvnrt.htm

*December 15, 2011*

**statistics**

z = (score - mean)/ standard deviation 1)Refer to the z-score chart. Look up the +z-score corresponding to a p-value of ~.8 2)Find score and round up to the nearest 10 interval.

*December 15, 2011*

**statistics (repeat)**

http://www.jiskha.com/display.cgi?id=1323980774

*December 15, 2011*

**physics**

Force = (mass)*(acceleration)

*October 30, 2011*

**chemistry**

Π = iMRT where Π = osmotic pressure in atm i = van 't Hoff factor of the solute. ((Broken Link Removed) M = molar concentration in mol/L R = universal gas constant = 0.08206 L·atm/mol·K T = absolute temperature in K

*October 29, 2011*

**Chemistry**

http://www.jiskha.com/display.cgi?id=1319910648

*October 29, 2011*

**physics**

Force = (mass)*(acceleration)

*October 2, 2011*

**MATH**

x= # kg of cashews 10-x = # kg of pecans ($8)(x) + ($9)(10-x) = $8.40 here's a similar problem: http://www.calculatorsoup.com/calculators/wordproblems/algebrawordproblem1.php

*October 2, 2011*

**chemistry**

2H2+O2->2H2O -convert g of H2 and of O2 each to mol H2O steps 2 & 3: http://www.jiskha.com/science/chemistry/stoichiometry.html -convert the one with lower mol H2O to grams -the reactant that produces the lesser amount of H2O is the limiting reagent and is the mass of water...

*October 2, 2011*

**statistics**

Find the p-value after you find the z-score. z = (x - μ) / σ http://www.ehow.com/how_4555631_calculate-zscore-statistics.html here's an example how to find the p-value: https://controls.engin.umich.edu/wiki/images/3/3e/Screen_shot_z-score.JPG The z-score is 1.13 ...

*September 30, 2011*

**Physics**

due north- aka find y-component due east- aka find x-component http://zonalandeducation.com/mstm/physics/mechanics/vectors/findingComponents/findingComponents.htm

*September 14, 2011*

**chemistry**

rule #2: http://www.seas.upenn.edu/~chem101/oxidationstates.html

*September 13, 2011*

**chemistry**

q = m x Cg x (Tf - Ti) http://www.ausetute.com.au/heatcapa.html

*September 4, 2011*

**Chemistry**

Do the following: 1) Balance the following: H2 + O2 -> H2O 2) Find the limiting reagent. The reactant (H2 or O2?) that produces the lesser amount of the product (H2O). http://www.chem.tamu.edu/class/majors/tutorialnotefiles/limiting.htm

*September 4, 2011*

**chemistry**

manipulate the units so that you end up with meters: (g)*(m/g) then convert to cm by multiply by 100

*September 2, 2011*

**Chemistry**

density = mass/volume mass = (density)*(volume)

*September 1, 2011*

**Calculating Averages?**

http://www.algebralab.org/practice/practice.aspx?file=algebra_averageatomicmass.xml

*August 29, 2011*

**geometry**

solve for x. (2x-3)=0 (x-5)=0 (4x+7)=0

*August 29, 2011*

**statistics**

Use the Empirical Rule. http://www.oswego.edu/~srp/stats/6895997.htm

*August 29, 2011*

**geometry**

http://arnoldkling.com/econ/GMU/growthArith.htm

*August 27, 2011*

**statistics**

http://www.ehow.com/how_4555631_calculate-zscore-statistics.html

*August 27, 2011*

**Statistics**

http://www.jiskha.com/display.cgi?id=1314477006

*August 27, 2011*

**statistics**

http://www.jiskha.com/display.cgi?id=1314477006

*August 27, 2011*

**statistic**

c is correct, but what about a and b? are they possible as well? What is a mode? Here are some examples: http://www.mathsisfun.com/mode.html http://www.purplemath.com/modules/meanmode.htm

*August 21, 2011*

**physical scince**

hint: density=mass/volume

*August 21, 2011*

**statsitsc**

http://stattrek.com/lesson2/normal.aspx

*August 20, 2011*

**physics**

Take the negative reciprocal of the slope. http://www.algebralab.org/lessons/lesson.aspx?file=geometry_coordparallelperpendicular.xml

*August 19, 2011*

**algebra**

Solve for x. This will give you a vertical line at whatever x value you get. Does it intersect the y axis? If not, there's no y-intercept.

*August 19, 2011*

**statistics**

hint: what does small sample size tell you about the standard deviation or variance (is it small or large?)?

*August 2, 2011*

**Algebra**

-10y/13=-4/3 cross multiply and solve for y (-10y)*(3)=(-4)*(13) http://www.mathsisfun.com/algebra/cross-multiply.html

*August 2, 2011*

**chemistry**

Molarity = moles of solute/ liter of solution convert g to mol by dividing molar mass 10g NaOH -> __ mol NaOH

*July 14, 2011*

**chemistry**

http://www.ausetute.com.au/heatcapa.html

*July 14, 2011*

**math**

5cm/20km = 17cm/x km cross multiply: 5x = (20)(17) solve for x.

*July 12, 2011*

**chemistry**

http://chemistry.bd.psu.edu/jircitano/soluble.html

*July 4, 2011*

**math**

http://www.mathsisfun.com/greatest-common-factor.html

*July 4, 2011*

**Science**

http://www.jiskha.com/science/chemistry/stoichiometry.html

*July 4, 2011*

**Algebra 1**

combine like terms: http://www.purplemath.com/modules/polydefs2.htm

*June 29, 2011*

**algebra/trignometry**

Draw a triangle. Label the angles x, y, and z. Label what are given. Determine whether what you have is SOH, CAH, or TOA. http://www.mathsisfun.com/algebra/sohcahtoa.html

*June 29, 2011*

**multiplying decimals**

http://www.mathsisfun.com/multiplying-decimals.html

*June 29, 2011*

**arithmetic**

http://www.mathwarehouse.com/algebra/averages/

*June 29, 2011*

**chemistry**

molality = moles of solute/ kg of solvent

*June 26, 2011*

**statistics**

sigma = sqrt [np(1-p)] http://stattrek.com/Lesson2/Binomial.aspx

*June 25, 2011*

**calculus**

Look at example 2: http://tutorial.math.lamar.edu/Classes/CalcI/DefnOfDerivative.aspx

*June 23, 2011*

**chemistry**

http://www.ndt-ed.org/EducationResources/HighSchool/Radiography/atomicmassnumber.htm

*June 21, 2011*

**Chemistry**

Calculate the Empirical Formula given 16.37% H and (100-16.37)% C. Refer to Example #2. http://www.chem.tamu.edu/class/majors/tutorialnotefiles/empirical.htm Use PV=nRT. n=mass/molar mass units: P=atm, V=L, T=K R=0.08206 atm*L/mol*k Solve for molar mass and calculate the ...

*June 21, 2011*

**MATH**

(1/6)^(3x) = 36 ^(2-x) hint: 1/6 = 6^(-1) & 36 = 6^2

*June 15, 2011*

**MATH**

(-1/18)*(r)=(1/6) find r. geometric progression: ar^(n-1) a=1st term r=ratio n=nth term http://www.mathsrevision.net/alevel/pages.php?page=33

*June 15, 2011*