Sunday

April 20, 2014

April 20, 2014

Total # Posts: 2,499

**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?

**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?

**Slavery **

how much were slaves paid after the civil war

**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.

**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

**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+

**Grammer Please Help!!**

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

**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 highe...

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

Thanks!!

**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...

**Speech**

thank you I appreciate your help:)

**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...

**Speech**

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

**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 conn...

**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 proce...

**math**

what is 9/2 - 1/2

**math**

what is 9/2 - 1/2

**chemistry**

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

**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...

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

thanks!

**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?

**Physics**

Thank you so much!

**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 wi...

**Math**

I don't know

**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 +...

**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...

**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?

**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?

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

thanks!

**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?

**chemistry **

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

**chemistry **

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

**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 0.0029...

**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?

**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

**chemistry**

lem;tdgpH:T

**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.

**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)

**Chemistry**

Write the name and chemical formula of an amphoteric ion.

**chemistry**

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

**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...

**Pre Calculus**

Thanks!

**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?

**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)...

**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.

**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 th...

**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

**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

**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.

**chemistry**

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

**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,...

**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...

**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 t...

**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

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

oops. thanks!

**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?

**11th grade math**

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

**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

**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

**biology**

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

**chemistry**

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

**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?

**Chemisty!**

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

**advance functions gr12 HELP ASAP**

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

**Math advance functions gr 12**

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

**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 wa...

**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...

**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.

**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...

**chemistry**

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

**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)

**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 collisi...

**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-statisti...

**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?

**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?

**math**

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

**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 i...

**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?

**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.

**chemistry**

dont answer i figured it out:D

**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 p...

**socials please check**

thank you :)

**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

**Socials please check my answers**

thanks :)

**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

**math**

thank you :D

**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.

**math**

help?

**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.

**grammer help**

thank you :)

**grammer help**

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

**science**

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

**science**

There are four forces in nature. Name the four forces and rank them from strongest to weakest.

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

Nevermind.. 1st problem was 6.25 and stayed at 6 because that would be the same amount for everyone. For #2, 3.75 was the average. But, need to stay at whole cup which would 3 for everyone to have equal amount, right?

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

oh.. so you multiplied 8 * 3 instead of 4. But, I thought I needed to round 3.75 up to 4. But, if using 8 *3, then 30-24 = 6. There are 6 cups left over. So, when shouldn't i round up? THe 1st problem with the pizza, I also rounded up.

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

So for #2, I should have divided by 8 members? 30/8 = 3.75; but 8*4 = 32 which is more than 30cups. I'm not sure how to solve this now.

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

I got these problems wrong in class. but, think i have the right answer now. Can you check? 1. Jim's mother made pizzas for his birthday. SHe sliced the pizzas into 50 slices. She served Jeff and his 7 guests the same number of slices and she ate the rest. How many pieces ...

**Math**

$27 is left.

**Social Studies**

Pacific.

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

Thank you Ms. Sue!!

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