# Posts by Alex

Total # Posts: 3,677

**chemistry**

a)Calculate the pH of a solution of 0.75 M HNO3, which is a strong acid. b)Calculate the pH of a 1.0 L aqueous solution made from 0.80 mol CH3COOH and 0.20 mol KCH3COO (Ka = 1.8 x 10^-5).

*May 9, 2013*

**chemistry**

How many moles of sodium nitrate are in 0.65L of a 0.2 M NaNO solution?

*May 7, 2013*

**5th grade Language Arts**

Thanks for checking!

*May 6, 2013*

**5th grade Language Arts**

I was given an assignment to add suffixes ( -ible, -ive, and -ion) to certain root words. I can't seem to find any words for post using the above suffixes. I've tried searching dictionary and roots with post. Are there any words that can be made without changing the ...

*May 6, 2013*

**5th grade math (word problems)**

Thanks! I see what I did wrong for #2.

*May 6, 2013*

**5th grade math (word problems)**

Can you explain how to do the following problems? 1. Order these fractions from Greatest to least. 3/12, 5/8, 1/4, 7/8, 4/16 work: find least common denominator 3/12 = 12/48, 5/8 = 30/48, 1/4 = 12/48, 7/8 = 42/48 answer = 7/8, 5/8, since 3/12 and 1/4 are the same, which would ...

*May 6, 2013*

**chemistry**

What is the difference between the two strong acids, nitric and hydrochloric acid, when they behave as the oxidised forms in a reduction half-equation?

*May 6, 2013*

**Maths**

168 children went to a them park. If 1/3 of the girls is equal to 4/9 of the boys, how many boys went to the theme park?

*May 6, 2013*

**Slavery**

how much were slaves paid after the civil war

*May 5, 2013*

**Chemistry**

Determine the solubility of a sodium sulfate, Na2SO4, in grams per 100g of water, if 0.94 g of Na2SO4 is dissolved in 20 g of water to make a saturated solution.

*May 3, 2013*

**Math**

The length of a rectangle is 11 cm less than 3 times its width. If the area of the rectangle is 20 square inches, find the length and width

*May 2, 2013*

**chemistry**

Reverse the reactions. Label the acids and bases on the left-hand side of each of the reversed equations? 1. HCl + NH3 => NH4+ + Cl- 2.NH3 + H2O => NH4+ +OH- 3. HCl +H2O => H3O+ +Cl- 4. H3PO4 +H20 => HPO4^-2 +H3O+ 5.H2PO4- +H2O => HPO4^-2 +H3O+

*May 2, 2013*

**Grammar Please Help!!**

Viewed through a telescope, the planet Mars looks rust-red. Because rust is a large component of its soil.

*May 2, 2013*

**chemistry**

1.Does a pH of 8.6 describe a solution with a higher or lower hydronium ion concentration compared to a neutral solution? Is such as solution called acidic or basic? 2. Compared to a neutral solution, would you expect an acidic solution to have a higher or lower pH and a ...

*May 2, 2013*

**5th grade math (word problems)**

Thanks!!

*May 2, 2013*

**5th grade math (word problems)**

I'm not sure how to solve this: A group of friends went to an amusement park. 10 of them rode the ferris wheel, 15 rode carousel, and 11 rode the roller coaster. 7 of them rode both the ferris wheel & roller coaster. 4 rode both the ferris wheel & carousel. 5 rode both the...

*May 2, 2013*

**Speech**

thank you I appreciate your help:)

*May 1, 2013*

**Speech**

Analysing errors consumes time and money. In order to assure that the physical erosion processes are correctly identified both error analysis and standardisation of measuring techniques are necessary to limit uncertainty and to minimise misinterpretation For the last paragraph...

*May 1, 2013*

**Speech**

thank you very much i will repost once i have finished the whole thing.

*May 1, 2013*

**Speech**

Soil erosion research is difficult for several reasons notably because it is an intermittent process and thus, an extremely difficult phenomena to observe. In most studies, only the consequences are investigated. Environmental data measurement, processing and analysis are ...

*May 1, 2013*

**Speech**

Please rephrase the following sentences into a more simple manner. I need to give a presentation and i would like to write this out simpler. Thank you guys Research of soil erosion is difficult for several reasons, but particularly because soil erosion is an intermittent ...

*May 1, 2013*

**math**

what is 9/2 - 1/2

*April 30, 2013*

**math**

what is 9/2 - 1/2

*April 30, 2013*

**chemistry**

a)Name two cations whose salts are quite soluble in water? b)Name one anion whose salts are soluble in water.?

*April 29, 2013*

**5th grade math (word problems)**

Maria is packaging boxes into a carton that is 4 in. x 6 in. x 3 in. THe boxes are 2 in. x 1 in. x 1 in. How many boxes will fit in the carton? I'm not sure how to solve. I know volume = l x w x h. The carton has volume of 72 cubic inches (4 x 6 x 3). THe boxes are 2 cubic...

*April 28, 2013*

**5th grade math (word problems)**

thanks!

*April 23, 2013*

**5th grade math (word problems)**

Problem: A receipe for 4 dozen cookies requires 1 1/2 cups of flour. How much flour is needed for 1 dozen? work: 4 divided by 1 1/2 = 4/1 x 3/2 = 4/1 x 2/3 = 8/3 cups of flour Can you explain why i don't need to change 4 dozen to 48 and then divide by 1 1/2?

*April 23, 2013*

**Physics**

Thank you so much!

*April 23, 2013*

**Physics**

21. The Mariana trench is located in the Pacific Ocean at a depth of about 10300 m below the surface of the water. The density of seawater is 1025 kg/m3. If an underwater vehicle were to explore such a depth, what force would the water exert on the vehicle's observation ...

*April 23, 2013*

**Math**

I don't know

*April 22, 2013*

**chemistry**

For each of the following primary standard acids, write the titration equation and calculate the volume of 0.100 M NaOH required for the titration: (i) 300 mg benzoic acid (C6H5COOH) (ii) 200 mg oxalic acid dihydrate (C2O4H2.2H2O) Equations: (i): C6H5COOH +NaOH->NaC6H5COO +...

*April 22, 2013*

**chemistry**

Calculate the weight (in mg) of borax Na2B4O7.10H20 required to react with 25.0 mL if 0.100 M HCI No. moles HCl consumed = __________ moles No. moles borax required = __________ moles Molar mass of borax = __________ g mol-1 (Na2B4O7.10H2O) Weight borax required = __________ g...

*April 22, 2013*

**chemistry**

15.0 mL of 8.00 M NaOH was diluted with water to 500 mL. Calculate the molarity of the diluted NaOH solution. My calculations: 0.015L x 8.00moles/1L x 39.997/1mole = 4.8g M= (4.8g x 1mole/39.997) / 0.500L = 0.24M is my workings correct? Is there another way to get to this?

*April 22, 2013*

**chemistry**

STANDARDISATION OF 0.1 M HCl Borax dissolves slowly in water at room temperature. Why do we not use a stirring rod to mix the solution and speed up this stage of the experiment?

*April 22, 2013*

**5th grade math (word problems)**

thanks!

*April 21, 2013*

**5th grade math (word problems)**

Mrs. Jones bakes pies. She always cuts each pie into 8 slices. Ther are 13 slices left on the counter. How many pies are on the counter? (write as mixed number). work: 13/8 = 1 5/8 pies. Is this correct?

*April 21, 2013*

**chemistry**

what is the h+ of a solution with a ph of 10 at 25 degree celsius

*April 21, 2013*

**chemistry**

in relation to the pH of pure water at 25 degree Celsius where do the pH values of acid fall

*April 21, 2013*

**chemistry**

A 0.0583 mol sample of formaldehyde vapour, CH2O, was placed in a heated 0.359 L vessel and some of it decomposed. The reaction is CH2O(g)---> H2(g) + CO(g). At equilibrium, the CH2O concentration was 0.0449 M. What is the value of Kc for this reaction? my answer was 0....

*April 20, 2013*

**chemistry**

At high temperature, 2.00 mol of CH2O was placed in a 4.00 L container where it decomposed via the equilibrium CH2O(g)<=>CO(g)+H2(g) . At equilibrium, the concentration of CO was measured to be 0.0317 M. What is Kc for this reaction at this temperature?

*April 20, 2013*

**Physics**

6. When a mass is attached to a spring, the period of oscillation is approximately 2.0 seconds. When the mass attached to the spring is doubled, the period of oscillation is most nearly a) 0.5 s b) 1.0 s c) 1.4 s d) 2.0 s e) 2.8 s

*April 19, 2013*

**chemistry**

lem;tdgpH:T

*April 17, 2013*

**Gifted Chemistry**

Calculate the freezing point and boiling point of a solution that contains 56.8 g NaCl and 32.0 g KBr dissolved in 750.3 mL H2O.

*April 16, 2013*

**Grade 12 Calculus**

Determine the velocity and acceleration as functions of time, t, for s(t) = 45t − 5t^2, where s(t) represents the distance as a function of time. (Hint: velocity and acceleration correspond to the first and second derivatives of the distance)

*April 15, 2013*

**Chemistry**

Write the name and chemical formula of an amphoteric ion.

*April 15, 2013*

**chemistry**

Name three sodium salts that produce weak bases in aqueous solution.

*April 15, 2013*

**Physics**

A small steel sphere of mass 0.40 kg is attached by a 0.50 m long cord to a swivel pin set into the surface of a frictionless table top. The sphere moves in a circle on the horizontal surface with a speed of 6.0 m/s. a.) what is the magnitude of the centripetal acceleration of...

*April 12, 2013*

**Pre Calculus**

Thanks!

*April 11, 2013*

**Pre Calculus**

Having trouble verifying this identity... cscxtanx + secx= 2cosx This is what I've been trying (1/sinx)(sinx/cosx) + secx = 2cosx (1/cosx)+(1/cosx) = 2 cosx 2 secx = 2cosx that's what i ended up with, but i know it's now right. did i mess up with the algebra?

*April 11, 2013*

**Physics Electric Force**

Particle A of charge 2.76 10-4 C is at the origin, particle B of charge -6.54 10-4 C is at (4.00 m, 0), and particle C of charge 1.02 10-4 C is at (0, 3.00 m). We wish to find the net electric force on C. (a) What is the x component of the electric force exerted by A on C? (b...

*April 11, 2013*

**Physics**

Particle A of charge 2.76 10-4 C is at the origin, particle B of charge -6.54 10-4 C is at (4.00 m, 0), and particle C of charge 1.02 10-4 C is at (0, 3.00 m). We wish to find the net electric force on C.

*April 11, 2013*

**Math**

In a recent year there were the following numbers (in thousands) of licensed drivers in the United States. MALE: Age 19 and under - 4746 Age 20 - 1625 Age 21 - 1679 FEMALE: Age 19 and under - 4517 Age 20 - 1553 Age 21 - 1627 Choose one driver at random. Find the probability ...

*April 10, 2013*

**Geography**

What is the best way to answer the following question? Where is the Sea of Okhotsk located? I know that is runs along the coastline of Russia, but I'm not sure what else I should add. thanks

*April 10, 2013*

**Geography**

How many degrees are there between the equator and the tropic of cancer? I think the answer is 23.5, is that correct? Thanks

*April 10, 2013*

**music**

i have to speak a hindi poem onany one of the- ''life and workings of Dr. B. R. Ambedkar'' ''vaisakhi'' ''the foundation of khalsa panth'' In poetry competition. So please help.

*April 10, 2013*

**chemistry**

I found K =1920 my question is whether the temperature is being used at all and if it is why?

*April 10, 2013*

**chemistry**

For reactions in solution, molar concentrations are usually used in equilibrium constant expressions (designated by K or Kc). In gases, partial pressures can also be used (designated by Kp). Equilibrium partial pressures of NOCl, NO and Cl2 in a container at 300 K are 1.2 atm...

*April 10, 2013*

**chemistry**

Hydrogen iodide reacts with itself to give hydrogen and iodine. The equilibrium constant is about 2.0 x 10─3 at a particular temperature. If you were to place some hydrogen iodide in a container and seal the container, what would you expect to find at equilibrium: mostly...

*April 10, 2013*

**Physics**

Please help! I've tried solving this with trig but I can't seem to figure out what I've been doing wrong. Two positive point charges, each of which has a charge of 2.3 × 10−9 C, are located at y = +0.60 m and y = −0.60 m. A)Find the magnitude of ...

*April 9, 2013*

**physics**

Blood takes about 1.50 s to pass through a 2.0-mm-long capillary. If the radius of the capillary is 5.00 um and the pressure drop is 2.60 kPa, calculate the viscosity of blood

*April 9, 2013*

**5th grade math (word problems)**

oops. thanks!

*April 7, 2013*

**5th grade math (word problems)**

Stefan pours 5/8 cup of milk. He uses 2/3 of it for a bowl of cereal. What fraction of a cup of milk does he use with his cereal? solution: 5/8 * 2/3 = 10/24 = 5/6. So, is the answer 5/6?

*April 7, 2013*

**11th grade math**

find the length of arc if an angle measuring 25 degrees is in the circle of radius 6 feet

*April 7, 2013*

**11th grade math**

in triangle DEF,<D=50 degree, DE=14 meters, and DF=10 meters. find the area of triangle DEFto the nearest tenth of a square meters

*April 7, 2013*

**Math**

in triangle DEF,<D=50 degree, DE=14 meters, and DF=10 meters. find the area of triangle DEFto the nearest tenth of a square meters

*April 7, 2013*

**biology**

90% if the released energy during the Krebs Cycle comes from what

*April 6, 2013*

**government**

The Senate?

*April 2, 2013*

**chemistry**

Calculate the new molarity when 150 mL of water is added to 125 mL of 8.55 M HBr.

*April 2, 2013*

**chemistry**

How many milliliters of commercial hydrochloric acid, which is 11.6 M, should be used to prepare 6.94 L of 0.52 M HCl?

*April 2, 2013*

**Chemisty!**

How many milliliters of concentrated ammonia, 15 M NH3, would you dilute to 250 mL to produce 0.162 M NH3?

*April 2, 2013*

**Alg 1**

Simplify. Write each answer in scientific notation. 1) (5.86 × 100 )(7.99 × 100 )

*April 2, 2013*

**advance functions gr12 HELP ASAP**

using rational functions solve (x+5)/(x-3)= (2x+7)/(x) thank you

*April 2, 2013*

**Math advance functions gr 12**

Using rational functions solve 7+ 1(numerator) x (denominator) = 1 (numerator) x-2(demominator)

*April 1, 2013*

**geology**

If the tilt of the earth’s axis increased to 30 degrees, which of the following statements would be correct? (a) There would likely be a greater variation between summer and winter positions of the Sub Tropical Ridge. (b) Summers are likely to become cooler and winters ...

*April 1, 2013*

**Math**

Hi i'm having trouble with a question. it states During the Summer you take 2 part time jobs. The first job pays $5 per hour. The 2nd Job pays $8 per hour. You want to earn at least $150 a week and work 25 hours or less a week. Write a system of inequalities that model the...

*March 27, 2013*

**5th grade math (word problems)**

Thank you! So, possible sizes are 6, 9, and 12. I really didn't need to use multiples of 4 at all.

*March 27, 2013*

**5th grade math (word problems)**

I'm not sure how to solve this problem. I know that i need to divide 36 cookies. But not sure how to figure out the number of groups. Am i using multiples of 4? Marie made 3 dozen cookies. She needs to dived them evenly into groups greater than 4. What are all the possible...

*March 27, 2013*

**chemistry**

how much toluene (C7H8) is need to make 47.3 (g) of TNT (C7H5N3O6) by the equation given below? C7H8+ HNO3 - C7H5N3O6 + H2O

*March 26, 2013*

**chemistry**

for the reaction of 14.69 g of ethyl alcohol with 22.5 g of oxygen. which is the limiting reagent? how much CO2 will be produced? if 19.5 g of CO2 is actually produced, what is the percent yield? C2H5OH(1) + 3 O2 (g) - 2 CO2 (g) + 3H2O(g)

*March 26, 2013*

**physics**

The figure shows a 0.3 kg baseball just before and just after it collides with a bat. Just before, the ball has velocity of magnitude 11.4 m/s and angle = 31.4 degrees. Just after, it is traveling directly upward with velocity of magnitude 9.00 m/s. The duration of the ...

*March 25, 2013*

**statistics**

In a recent study on gender differences in education, a sample of 7 boys had a mean score of 18.5 and a standard deviation of 4.1 on a Standardized Math Test. A sample of 11 girls had a mean score of 19.9 and a standard deviation of 3.6 on the same test. What is the t-...

*March 24, 2013*

**physics**

a positive test charge of 3.0uC experiences a force of 0.75 N in an electric field. What is the magnitude of the electric field at the location of the test charge?

*March 23, 2013*

**physics**

a positive test charge of 3.0uC experiences a force of 0.75 N in an electric field. What is the magnitude of the electric field at the location of the test charge?

*March 23, 2013*

**math**

Which equivalent fraction would you have to use in order to add 3/5 to 21/25

*March 21, 2013*

**chemistry**

Condition Pressure Volume Temperature Comment initial 1.0 atm 22.4 L 273 K 1 mole of N2 gas fills the tank. final 3.0 atm 22.4 L 273 K 2 moles of O2 gas have been added to the 1 mole of N2 gas in the tank. Key Questions 7. What was the initial pressure caused by the nitrogen ...

*March 21, 2013*

**chemistry**

The mole fraction of oxygen in air is 0.209. Assuming nitrogen is the only other constituent, what are the partial pressures (in torr) of oxygen and nitrogen when the barometer reads 780 torr?

*March 20, 2013*

**chemistry**

Calculate the partial pressure of 3.25 moles of oxygen that have been mixed (no reaction) with 1.25 moles of nitrogen in a 25.0 L container of 298 K.

*March 20, 2013*

**chemistry**

dont answer i figured it out:D

*March 20, 2013*

**chemistry**

Mixtures of helium and oxygen are used in scuba diving tanks to help prevent ‘the bends’, a condition caused by nitrogen bubbles forming in the bloodstream. If 95 L of oxygen and 25 L of helium at STP are pumped into a scuba tank with a volume of 8.0 L, what is the ...

*March 20, 2013*

**socials please check**

thank you :)

*March 19, 2013*

**socials please check**

how many time zones are there in canada? My options are: a.) 5 b.) 10 c.) 7 though i tried answering this and i got 6? what is the correct answer

*March 19, 2013*

**Socials please check my answers**

thanks :)

*March 19, 2013*

**Socials please check my answers**

pleaes chack my answers: what are the horizontal lines on a map called? my answer= latitudes what are the vertical lines on a map called my answer= longitudes

*March 19, 2013*

**math**

thank you :D

*March 18, 2013*

**math**

There are 3 pitchers of juice. Each student will be served one fourth of the juice in a pitcher. How many students will get juice? l a. Draw lines on the pitchers to show how many students these pitchers will serve. b. Write a number model to describe the problem.

*March 18, 2013*

**math**

can someone please help me cause its almost 10 were i am

*March 18, 2013*

**math**

There are 3 pitchers of juice. Each student will be served ^ of the juice in a pitcher. How many students will get juice? l a. Draw lines on the pitchers to show how many students these pitchers will serve. b. Write a number model to describe the problem.

*March 18, 2013*

**grammar help**

thank you :)

*March 11, 2013*

**grammar help**

Aunt Dessie unfolded out of the car like a carpenter’s ruler” is an example of personification. symbol. simile. metaphor.

*March 11, 2013*

**science**

There are three particles inside an atom. One of them has zero electric charge. Which one is it?

*March 10, 2013*