Saturday

April 19, 2014

April 19, 2014

Total # Posts: 179

**chemistry**

The Henry's law constant for CO2 at 20°C is 3.7*10^-2 M/atm. What mass of CO2 (in grams) is present in 355 mL of soda drink if the pressure of CO2 in the can is 2.5 atmospheres at 20°C? (Assume the solubility of CO2 in the soda is the same as water)

**SAT prep help**

if -2x+5=2-(5-2x), what is the value of x?

**Chemistry**

Write the total and net ionic equations for the following molecular reaction: HgNO3 (aq) + NaCl (aq) -> HgCl (s) + 2 NaNO3 (aq)

**math**

Gail and 3 friends all share 1/2 a pie. All the pieces in pie put together make up 180 degrees. Gail and friends finish the pie and each eat an equal piece. They believe each piece has an angle of 25 degrees. Are they right?

**chemistry**

How many grams of I2 are present in a solution if 33.75mL of 0.140M Na2S2O3 solution is needed to titrate the I2solution?

**math**

A t-shirt manufacturer uses 5/8 yard of material for each shirt, how many shirts can be made fro 14 & 38 yards of material?

**math 15**

find the minimum height above the surface of the earth so that the pilot at point a can see an object on the horizon at c 125 miles away. assume the diameter of the earth to be 8000 miles.

**Macroeconomics**

If the government imposes a price ceiling of $100 on a market, what would happen in the market as a result of protests of price gauging by the sellers? What would happen to the price and quantity in the market?

**Pre Calc 12**

Four consecutive integers have a product of 360 Find the integers by writing a plynomial equation that represents the integers and then solving algebraically.

**Pre Calculus**

mx3-nx2+5x-1 is divided by x-2 the remainder is -39. When divided by x-1 the remainder is 3. What are the values of m and n. Didn't know how to do the superscript for mx3

**chemistry**

thanks steve :)

**chemistry**

how many molecules are present in 1.2 mol of glucose, C6H12O6?

**science**

What does chlorophyll do for plants?

**literature**

What are the major events in Act I of A Doll's House?

**Algebra**

Solve using set builder notation, show all work. 12x-25 is greater than or = to 3x-5(x+6)

**math**

A square is made up of section A and section B. Section A is 500 sq. ft. and section B is 750 sq. ft. What percent of the square is section A? *

**math help**

Universal instruments found that the monthly demand for its new line of Galaxy Home Computers t months after placing the line on the market was given by D(t) = 2900 − 2300e−0.08t (t > 0) Graph this function and answer the following questions. (a) What is the dem...

**math help**

determine the intervals where f(x) = e^((-x^2)/2) is increasing and where it is decreasing

**algebra**

What is the answer for 4.(5)(5)-35+21-(-3)(-3)(-3)

**Inverse Functions**

Given that g is the inverse function of f, and f(3)=4, and f'(3)=5, then g'(4)= ?

**math**

thank you for your help

**math**

The call letter of a radio station must have 4 letters.The first letter must be a K or a W. How many different station call letters can be made if repetitions are not allowed? *(If repetitions are allowed?)* *Important

**math**

The call letter of a radio station must have 4 letters.The first letter must be a K or a W. How many different station call setters can be made if repetitions are not allowed? If repetitions are allowed? I have the answers just need to know the work

**biology**

what all do i need to know for GCSE biology my teacher is absolutely rubbish i tried websites but i don't find them helpful thankyou

**Chemistry**

The formaldehyde content of a pesticide preparation was determined by weighing 0.3124g of the liquid sample into a flask containing 50.0mL of 0.0996M NaOH and 50mL of 3% H2O2. Upon heating, the following reaction took place: OH- + HCHO + H2O2 -> HCOO- + 2H2O After cooling, ...

**Chemistry**

A 25.00mL sample of a household cleaning solution was diluted to 250.0mL in a volumetric flask. A 50.00mL aliquot of this solution required 40.38mL of 0.2506 M HCl to reach a bromocresol green end point. Calculate the weight/volume percentage of NH3 in the sample. (Assume that...

**Chemistry**

What is the likely source of error from reading a graph where the absorbance (y-axis) versus concentration (x-axis) shows non-deal behaviour. The graph is going in what looks like a line of best fit but then curves off a the end. At the end of the graph there is a curve and it...

**Spanish-SraJMcGinthank you**

Thank you so much for explaining it-I think I got it this time.

**Spanish-SraJMcGin please help ?**

I'm so confused with these-please check them. ¿Estudias algo los sábados? No, no estudio nada los sábados.Do I need the no, no or just one no, estudio? ¿Hablas a francés a veces? No, no hablo nunca a francés. Once again, do I need ...

**Spanish-Check please! I need help**

Please check-I'm having a problem interpreting these questions and I have to answer them for homework. Could you please check my translation I'm not sure what these questions mean and I have to answer them for homework ¿Qué necesitas para comer en cereal?...

**Spanish-Thank you both for assisting-I really appreciate it-**

Thank you both for helping I appreciate it - I rechecked the first question-I copied it exactly as it was written so I'll just answer it as if I need a bowl, spoon, etc. Thank you again.

**Spanish-Help Please**

Thank you for doing that-I'm stuck on these questions

**Spanish-Help Please**

I'm not sure what these questions mean and I have to answer them for homework ¿Qué necesitas para comer en cereal?does this ask what I need to eat cereal-like a spoon , bowl etc? 2. ¿Qué ríes mucho cuándo miras a los payasos?Do you...

**Spanish-Please check answers**

Thank you for the corrections- I always forget that "a"

**Spanish-Please check answers**

Thanks alot-I really appreciate it Ms. Sue

**Spanish-Please check answers**

Él no va nunca.He never goes Él ve alguien.He sees someone. Él no ve nadie.He doesn’t see anyone.

**Physics**

Consider a frictionless track as shown in the figure below. A block of mass m1 = 5.75 kg is released from A. It makes a head on elastic collision at B with a block of mass m2 = 8.00 kg that is initially at rest. Calculate the maximum height to which m1 rises after the collisio...

**uncc**

the half-life of 234U, uranium-234, is 2.52 x 10^5yr. If 98.5% of thee uranium in the original sample is present, what length of time (to the nearest thousand years) has elasped

**Chemistry**

Calculate the pH of a 0.10 M NaHX salt solution. Ka (H2X) = 2.1 x 10-2 Ka (HX-) = 4.5 x 10-8 Can someone explain the steps to do this please?

**physics**

A projectile is fired straight up at a speed of 15 m/s. How long does it take to reach the top of its motion? The acceleration of gravity is 9.8 m/s2 .

**physics**

A projectile is fired straight up at a speed of 15 m/s. How long does it take to reach the top of its motion? The acceleration of gravity is 9.8 m/s2 .

**calculus**

find all points at which the tangent line to the graph of y=x3 is parallel to the line y=27x+5

**Physics**

Two objects attract each other gravitationally with a force of 2.9 10-10 N when they are 0.29 m apart. Their total mass is 4.0 kg. Find their individual masses.

**science**

One of the characters Mendel studied was the position of the flowers. He crossed plants that had flowers at the tips of the stems with plants that had flowers along the sides. He allowed the F1 plants, which had flowers along the sides, to self-fertilize. In the F2 generation,...

**science**

A segment of double-stranded DNA contains 31% Adenine (A) bases. a. What are the percentages of the other three bases in the DNA segment? (Count bases on both strands.) C: T: G:

**science**

There are about 300,000,000 US citizens. If we wanted to assign each person a unique identifier, using DNA sequences, how long a DNA sequence would we need? (Here’s another way of phrasing the question: How many bases of DNA are required for there to be at least 300 milli...

**Math**

The measure of one angle in a linear pair is 30 more than twice the measure of the other angle. Find the measure of the angles. (I really need help! Thanks)

**chemistry**

A glass apparatus contains 26.223 g of water when filled at 25 °C. At this temperature, water has a density of 0.99704 g/mL. What is the volume of this apparatus?

**chemistry**

A glass apparatus contains 26.223 g of water when filled at 25 °C. At this temperature, water has a density of 0.99704 g/mL. What is the volume of this apparatus?

**chemersty**

Calculate the value of the following in exponential form, using standard scientific or "e" notation (for example, 105 = 1.05e2). Enter your answer with the correct number of significant figures. 885.75 g + 10.151 g - 25.50 g

**Maths**

Stuck! Help! 2.5 cubed? Xxxxx

**math**

in a distribution of 160 values with a mean of 72,at least 120 fall within the interval 67-77. approximately what percentage of values should fall in the interval 62-82? use chebyshev's formula.

**science**

please help!

**science**

lena carried out an investigation to find the energy content in bacon rind she lit the bacon rind with a bunsen burner and held it beneath a test tube of water she stirred the water and recorded it temperature! why did lena stir before recording the temperature?

**science**

does noone know

**science**

please help

**science**

urgent

**science**

the list below shows three ways in which metals can react. a) strongly heat the metal in the air. b)add small pieces of the metal to cold water. c)add small pieces of the metal to dilute acid. in each case choose a b or c calcium oxide hydrogen (using zinc) magnesium chloride ...

**Physics**

My teacher didn't specify if 9.821 m/s^2 is the value of the North Pole. We don't have class this week because of Spring Break and it's due the morning we get back, so I can't ask him any questions. But I got C through F now, thank you!

**Physics**

Consider a pendulum of length 4.557 m. The acceleration of gravity is 9.832 m/s2 . a) What is its period at the North Pole? Answer in units of s. b) What is its frequency? Answer in units of Hz. c) What is its period in Chicago, where g = 9.803 m/s2? Answer in units of s. d) ...

**Physics**

A trapeze artist swings in simple harmonic motion with a period of 3.2 s. The acceleration of gravity is 9.81 m/s2 . Calculate the length of the cables supporting the trapeze. Answer in units of m.

**Physics**

A mass of 0.38 kg is attached to a spring and is set into vibration with a period of 0.22 s. What is the spring constant of the spring?

**math (calculus)**

A cap of a sphere is generated by rotating the region about the y-axis. Determine the volume of this cap when the radius of the sphere is 5 inches and the height of the cap is 1 inch.

**math (calculus)**

A cap of a sphere is generated by rotating the region about the y-axis. Determine the volume of this cap when the radius of the sphere is 5 inches and the height of the cap is 1 inch.

**Physics**

The hoover dam produces 2x10 to the 9 W of electricity. It is composed of 7x10 to the 9 kg of concrete. To produce 1 kg of concrete requires 1 MJ of energy. How much energy did it take to produce the dam? How long was the "energy payback time" for the dam? The area o...

**Physics**

the relationship between rotational speed and net force is direct right? and also can u say why it is direct

**physical science 2**

It takes 6 seconds for a stone dropped from rest to the bottom of a well,what is its final speed A; 6 meters/second B: 30 meters/seconds C: 36 meters/seconds D: 60 METERS/SECONDS A is incrrect

**Physical Science 2**

Ten seconds after starting from rest,a freely falling object will have a speed of about______ rn/s A: 10 B: 50 C: 100 D: 120 I know that the answer A is not correct.

**physical science 2**

A block is dragged at constant velocity in a straight line path across a level surface by force of 6 N. What is the friction between the black and the surface? a: 6 N B: less than 6 N C: More than 6N d: ZERO

**physical science 2**

the force required to maintain an object at a constant velocity in free space is equal to: b: the mass of the object. c: the force required to stop it. d zero

**physical science**

A kg ball of lead rests next to a 10 kg rock. which statement below is true:a:the lead ball and rock have the same amount of inertia,b:if the lead ball and the rock fell from the same height in a vacuum, the rock would hit the ground first because it is less massive,c: on the ...

**physical science**

a car traveling in a lage circlepasses by a motorcycle that is trveling in a straight line north to south.both of their speedometers read 10m/s.which statement is true; a: the car and motorcycle have the same speed ,but different velocities,b:the car and motorcycle have the sa...

**physics**

The centers of a 6.0 lead ball and a 70 lead ball are separated by 8.0 . What gravitational force does each exert on the other? What is the ratio of this gravitational force to the weight of the 70 ball?

**Chemistry**

A calorimeter contains 21.0 mL of water at 14.0 degreesC. When 1.90 g of X (a substance with a molar mass of 70.0 g/mol) is added, it dissolves via the reaction X(s)+H_2O(l)reacts to make X(aq) and the temperature of the solution increases to 28.5degreesC. Calculate the enthal...

**Chemistry**

80.0 mL of water is initially at room temperature (22degrees C). A chilled steel rod at 2 degrees C is placed in the water. If the final temperature of the system is 21.2 degrees C, what is the mass of the steel bar? Specific heat of water = 4.18J/g(degreesC) Specific heat of ...

**Chemistry**

sorry. didn't mean to post twice

**Chemistry**

Helium-oxygen mixtures are used by divers to avoid the bends and are used in medicine to treat some respiratory ailments. What percent (by moles) of Helium is present in a helium-oxygen mixture having a density of 0.538 g/L at 25 degrees C and 721 mmHg? Express your answer num...

**Chemistry**

Helium-oxygen mixtures are used by divers to avoid the bends and are used in medicine to treat some respiratory ailments. What percent (by moles) of helium is present in a helium-oxygen mixture having a density of 0.538 g/L at 25 degrees C and 721mmHg? Express your answer nume...

**Chemistry**

Typically, when a person coughs, he or she first inhales about 2.50 L of air at 1.00atm and 25 degreesC. The epiglottis and the vocal cords then shut, trapping the air in the lungs, where it is warmed to 37 degrees C and compressed to a volume of about 1.70L by the action of t...

**Chemistry**

Redox titrations are used to determine the amounts of oxidizing and reducing agents in solution. For example, a solution of hydrogen peroxide,H2O2, can be titrated against a solution of potassium permanganate, KMnO4. The following equation represents the reaction: 2KMnO4(aq)+H...

**Chemistry**

A volume of 50.0 mL of aqueous potassium hydroxide was titrated against a standard solution of sulfuric acid. What was the molarity of the KOH solution if 19.2 mL of 1.50 M H2SO4 was needed? The equation is 2KOH(aq) +H2SO4(aq)-» K2SO4(aq)+2H2O(l)

**physics**

A duck has a mass of 2.3 kg. As the duck paddles, a force of 0.07 N acts on it in a direction due east. In addition, the current of the water exerts a force of 0.26 N in a direction of 48° south of east. When these forces begin to act, the velocity of the duck is 0.15 m/s ...

**math**

i have 3 pints oil and 12 gallons of gas,each lawn mower uses 0.5 pints of oil and 1.5 gallons of gas. How many days can she mow lawns?

**chemistry**

Thank you! Now I am having problems with part e.

**chemistry**

I put in the wrong numbers for the second part.

**chemistry**

I can't figure out how to get the initial pH. Also, when I tried part B I used 21.0 mL*.100M=XmL*0.130 and it wasn't the correct answer.

**chemistry**

Consider the titration of 21.0 mL sample of 0.110 M HC2H3O2 with 0.130 M NaOH. what is the initial pH? what is the volume of added base required to reach equivalance point? what is the pH at 5.00 mL of added base? pH at one half o the equivalence point? pH at the equivalence p...

**chemistry**

Calculate the pH of the solution that results from the mixture. 170 mL of 0.12 M C2H5NH2 with 285.0 mL of 0.22 M C2H5NH3Cl.

**chemistry**

what is the pH of 0.15 M NaF?

**chemistry**

If 5.05mL of 0.1000 M NaOH solution is needed to just neutralize excess acid after 20.00 mL of HCl was added to 1.00 g of an antacid, how many moles of acid can the antacid counteract per gram?

**chemistry**

If 5.00 mL of HCl require 4.03 mL of 0.9581 M NaOH to just consume the HCl, what is the concentration of the HCl?

**chemistry**

need help with these problems: The concentration of glucose in blood is usually about 0.10% (w/v). If 7.0 L of blood are in an average man, how many grams of glucose are in his blood? To obtain the solute for 118 g of a 19.2% (w/w) solution of sugar we would weigh out ________...

**chemistry**

need help setting this problem up: The heat of fusion of water is 335 J/g. How much heat would be required to melt 10.4 g of ice?

**Chemistry**

The following reaction was monitored as a function of time: AB--->A+B A plot of 1/[AB] versus time yields a straight line with slope 5.2×10−2 . If the initial concentration of is 0.240M , and the reaction mixture initially contains no products, what are the conc...

**chemistry**

The following reaction was monitored as a function of time: AB--->A +B A plot of 1/[AB] versus time yields a straight line with slope 5.2 x 10^-2 M*s. What is the value of the rate constant (k) for this reaction at this temperature?

**ch102**

The rate constant of a reaction at 30 was measured to be 5.7×10^-2. If the frequency factor is 1.2 x10^13 /s what is the activation barrier?

**CH102**

nevermind! figured it out

**CH102**

If a temperature increase from 18.0 to 34.0 triples the rate constant for a reaction, what is the value of the activation barrier for the reaction?

**Chemistry**

i tried that but it says its wrong