Posts by alex

Total # Posts: 3,749

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)
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....

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

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.

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 ...

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 ...

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 um 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?

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

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

government
The Senate?

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?

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

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 ...

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 ...

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-...

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 ...

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 ...

thank you :)

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

thanks :)

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

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.

grammar help
thank you :)

grammar 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!!

5th grade math (word problems)
I'm not sure how to solve the following problem. I don't think i have enough information. Ali deposited \$120 in her savings account. This represents 75% of the money she received for her birthday. She pent the rest of her money on a lego toy. How much did the lego cost...

english
Clark sees that the wind in the nebraska setting has changed aunt georgina by? A. bending her shoulsers B. rotting her teeth C. yellowing her skin D. dirttying her clothes

spanish
this is part of a spanish project and i need to know if i placed the accent marks correctly or forgot to put some of them. please help! Inglés Matemáticas Ciencias Sociales Ciencias Naturales Arte Música Geometria Biologia Hay que llevar el carnet de ...

Social studies
what are the 50 us states postal abbreviations and state numbers?

algebra one
{n|n<13} which is the same as n<13

Physics
A 100 watt bulb emits light in all directions. The distance R from the bulb is equal to 1.0 meter. Complete the table below with calculated values of intensity of the bulb. Distance from Source Intensity (W/m2) R ? 2R ? 3R ? c) If the bulb was replaced by a 75 watt bulb, at ...

Physics
A radio tunes in radio waves which have a wavelength of 3.13 meters. What frequency is the radio tuned to in MHz?

Physics
An astronomer looks at a comet which is 5.92 x 109 km away. How many minutes did it take the light from the comet to reach the astronomer?

4 Quarters times 8 Minutes times 7 games is 224 minutes.

physical science
Boyle’s law states that if you squeeze a fixed amount of a gas into a smaller volume, the pressure will increase. Explain why?

chemistry
Hey, I was just struggling with a question that I need to figure out to help me with my next lab, so if any of you guys could help me that would be greatly appreciated. Question: write a balanced equation for the reaction between H2O2 and acidified MnO4-

Math
6_5

Math for Ms. Sue please! Last math questions!
Thank you sunny dreams i got 100%

physical science
Boyle’s law states that if you squeeze a fixed amount of a gas into a smaller volume, the pressure will increase. Explain why?

physical science
10. A balloon has a volume of 0.5 L at 20°C. What will the volume be if the balloon is heated to 150°C? Assume constant pressure and mass.

physical science
3. Atmospheric pressure at the top of Mt. Everest is about 150 mm Hg. That is why climbers always bring oxygen tanks. If a climber carries a 12.0 liter tank with a pressure of 35,000 mm Hg, what volume will the gas occupy if it is released at the top of Mt. Everest?

physical science
3. Atmospheric pressure at the top of Mt. Everest is about 150 mm Hg. That is why climbers always bring oxygen tanks. If a climber carries a 12.0 liter tank with a pressure of 35,000 mm Hg, what volume will the gas occupy if it is released at the top of Mt. Everest?

physical science
Boyle’s law states that if you squeeze a fixed amount of a gas into a smaller volume, the pressure will increase. Explain why? this is the answer

physical science
I was not wrong

physical science
1. Boyle’s law states that if you squeeze a fixed amount of a gas into a smaller volume, the pressure will increase. Explain why in your own words.

chemistry
What volume (mL) of a 3.23 %w/v saline solution contains 69.1 mg of NaCl?

science
3. Atmospheric pressure at the top of Mt. Everest is about 150 mm Hg. That is why climbers always bring oxygen tanks. If a climber carries a 12.0 liter tank with a pressure of 35,000 mm Hg, what volume will the gas occupy if it is released at the top of Mt. Everest?

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