# Posts by Lyndsay

Total # Posts: 56

**Chemistry**

If a spectrophotometer was not zeroed before making measurements, what effect would it have on the calibration curve?

**Chemistry**

What is the numerical relationship between the volume of base added to reach the first endpoint and the volume added to reach the final endpoint in the titration of a diprotic acid? What is the relationship for a triprotic acid?

**Math**

w^3 + 343/ w^11 - 49W^9 (times) w^12 -14w^11 +49w^10/ w^2-7w +49

**Physics**

A brick is thrown upward from the top of a building at an angle of 19.3? above the horizontal and with an initial speed of 22.5 m/s. The acceleration of gravity is 9.8 m/s2 . If the brick is in ?ight for 3.5 s, how tall is the building? Answer in units of m

**Physics **

When an objects acceleration is 0 at an instant t in time, its velocity is 1. zero at t. 2. negative at t. 3. positive at t. 4. not changing at t. My teacher never taught us this, can someone help me figure it out?

**Physics**

I am unsure how to solve for V when given the circumference instead of the radius.

**Physics**

A 905 kg test car travels around a 3.34 km circular track. If the magnitude of the force that maintains the car’s circular motion is 2134 N, what is the car’s tangential speed? Answer in units of m/s.

**Biology**

In the 1940’s, Avery, MacCleod, and McCarty transformed nonencapsulated bacteria into encapsulated forms by growing the nonencapsulated cells in a cultre containing an extract made from dead encapsulated cells. The transformed cells produced colonies of encapsulated...

**Physics**

A horse of mass 187 kg pulls a cart of mass 200 kg. The acceleration of gravity is 9.8 m/s2 . What is the largest acceleration the horse can give if the coe?cient of static friction between the horse’s hooves and the road is 0.612? Answer in units of m/s2.

**Physics**

Can someone please walk me through what equation I need to use to do this?

**Physics**

I tried this problem with a=2(l)/t^2, a=2(3.2)/3.95^2 = 0.41019 and the answer is not correct and I am not sure what is wrong with it or how to do it.

**Physics**

A block is released from rest on an inclined plane and moves 3.2 m during the next 3.9 s. The acceleration of gravity is 9.8 m/s2 . What is the magnitude of the acceleration of the block? Answer in units of m/s2. The block is 12kg and the incline is 36 degrees.

**Chemistry **

Using the following bond energies, calculate the molar heat of hydrogenation, ?Hhydrogenation, for the conversion of C2H2 to C2H6 CH (triple bond) CH (g) + 2H2 (g) --> CH3CH3 (g)

**Biology **

Glycolysis produces ATP through what process?

**Biology **

Glycolysis produces ATP through what process?

**Chemistry**

The formation of tetrafluoroethylene from its elements is highly exothermic: 2F2(g) + 2C(s) <-> F2C=C2F(g) b) Rare bacteria from the planet Teflon eat C2F4 and make Teflon for their cell walls. Will the reaction go to the right or left if these bacteria are added? Right ...

**Physics**

A - A girl delivering newspapers covers her route by traveling 4 blocks west, 2 blocks north, then 6 blocks east. What is her resultant displacement? Answer in units of blocks. B - What is her direction? Use counterclockwise as the positive angular direction from due east, ...

**Chemistry**

Conclusions about the best indicator to use- Consider the pKa of indicator in relation to equivalence point of reaction, ease of seeing the endpoint color change, precision of measurements,etc. Which indicator would you choose if planning an experiment and why? Could you use ...

**Chemistry**

The price of a popular soft drink is $0.980 for 24.0 oz (ounces) or $0.780 for 0.500 L. 1 qt = 32.0 oz. What is the price per liter of the 24.0 oz bottle? What is the price per liter of the 0.500 L bottle?

**Chemistry**

A dye has a ?max = 460 nm (? = 70,000 L/(mol*cm)). What is the concentration of dye in a sample whose absorbance at 460 nm is A = 0.350 in a cell with a path length of 1.00 cm (4 points) I have no idea how to do this.

**Chemistry help!!**

Calculate the concentration of a solution prepared by adding 15.00 mL of 2.10 X 10^-3 M KMnO4 from a buret into a 50.00 mL volumetric flask, which is then filled to the 50.00 mL graduation mark with distilled water.

**Chemistry help!!**

I figured that out but I need help with this one: How many moles of P4 would be required to produce the number of moles of H3PO4 determined from the question above which the answer is 2.34 for above.

**Chemistry help!!**

Phosphoric acid, H3PO4, has some important applications. It can be used to produce fertilizers and it is present in soft drinks. Phosphoric acid can be made from phosphorus in a two step process: Reaction 1: P4 + 5 O2 --> P4O10 Reaction 2: P4H10 + 6H2O--> 4H3PO4 A ...

**Chemistry help!!**

Potassium perchlorate decomposes as follows: KClO4 (s) --> KCl (s) + 2 O2 (g) If 269 mL of wet O2 (g) is collected over water at 25 c (vapor pressure= 23.8 torr) and the barometric pressure is 748.0 torr, how many grams of potassium perchlorate have decomposed?

**Chemistry **

Potassium perchlorate decomposes as follows: KClO4 (s) --> KCl (s) + 2 O2 (g) If 269 mL of wet O2 (g) is collected over water at 25 c (vapor pressure= 23.8 torr) and the barometric pressure is 748.0 torr, how many grams of potassium perchlorate have decomposed?

**Chemistry**

What volume of N2O (s) will be generated if 3.13 g of NH4NO3 (s) decomposes at 1.00 atm and 50 degrees celsius, given the following decomposition reaction: NH4NO3 (s) --> N2O (g) + 2 H2) (l)?

**Chemistry**

Why doesn't acetylation occur twice on the same ring? Please help, I have no idea.

**Physics**

In a rectangular coordinate system, a positive point charge 5.0 nC is placed at the point x=0, y=2.0 cm, and a negative point charge -5.0 nC is placed at x=0, y=-2.0 cm. Both charges have masses 4.0x10^-3 g. Point P is at x=3.0 cm, y=2.0 cm. The electric potential at infinity ...

**Chemistry**

draw the product of di-acetylation of biphenyl. Explain why acetylation does not occur twice on the same ring. I have no idea how to do this

**Chemistry**

How would you know which one is the polar solute?

**Chemistry**

yes it is a polar solvent

**Chemistry**

Consider compounds trans-4-tert-butylcyclohexanol and 4-tert-butylcyclohexanone below. Using silica gel TLC plates, which of these two compounds will have the higher Rf value when dichloromethane is the developing solvent? Why? Does it possibly have to do with the polarity?

**Chemistry**

Based on chemical structures, explain why acetophenone is only separated at the end by distillation. The mixture was acetophenone and ethyl trimethylacetate

**Organic Chemistry**

Explain why the formation of one geometric isomer is favored over the other?

**Calculus**

find the point on the plane 5x+4y+z=12 that is nearest to (2,0,1)

**Chemistry**

What is the value for Kb for the formate anion, HCOO-? Ka(C7H5O2)=2.1x10^-4.

**Calculus**

Compute the curvature. r(t)=(t^2,2t^3/3) t >0 The answer is 1/2t(1+t^2)^3/2 I have tried multiple times but i cannot arrive to this answer.

**Chemistry**

If all of the SCN- was not converted completely converted to FeNCS^2+ when the calibration curve was prepared, would this raise or lower the value of Keq? Explain

**Biology**

Use your understanding of natural selection to describe how the following trait might have evolved: Plants have pores on the surfaces of their leaves that allow carbon dioxide into the leaf (for photosynthesis), but also allow water to escape. Land plants have guard cells ...

**Chemistry**

What is the pressure of 1.78 g of nitrogen gas confined to a volume of .118 L and 25 degrees Celsius?

**chemistry**

nevermind i figured them out

**chemistry**

Write the molecular,complete ionic, and net ionic equations for the reactions that occur, if any, when solutions of the following substances are mixed: a) nitric acid and potassium carbonate b) sodium bromide and lead nitrate c) acetic acid and calcium hydroxide d) calcium ...

**general chemistry**

How many oxygen atoms are in 3.90 g of quartz?

**math**

I am solving a problem and have -cos(a)=-1/2. How do I solve for a?

**ap calc**

Find the area of the shaded region, bounded by the parabola 16y=5x^2+16 and the lines y=0, y=6, and x=5. I broke the figure up into two parts and got 3102/5. It seems like a large answer am I correct? Your help is greatly appreciated.

**AP Calc**

If y= (e^x-e^-x)/(e^x+e^-x), then y'= I took the derivative and got: y'=(e^x+e^-x)(e^x+e^-x)-(e^x-e^-x)(e^x-e^-x)/(e^x+e^-x)^2 I know the correct answer is 4/(e^x+e^-x)^2

**Government**

What is one specific example of why a person would be summoned to the Erie County Supreme Court? I know that the Erie County Supreme Court deals with criminal and civil cases.

**Psyc, statistics**

Introduction to Hypothesis Testing In an article entitled “Science and ethics in conducting, analyzing, and reporting psychological research” in the journal Psychological Science (1994), psychologist Robert Rosenthal examines the relationship between a researcher&#...

**Math**

Dorothy and Rosanne are baking cookies for a party. Working alone, Rosanne can finish the cookies in 6 hours. Dorothy can finish them in 8 hours if she is working alone. How long will it take them to bake the cookies if they are working together? Round your answer to the ...

**English**

Decide which of the two reasons offered in each instance will be more persuasive to the specified audience.Write out the implied warrant for each "because" clause and explain whether the specific audience will likely grant it or not. 1)Audience:people who advocate a ...

**health and diseases**

this was not very helpful but thanx anyways.

**health and diseases**

I need a little help with an analogy for Nephrogenic diabetes insipidus. I'm not sure excatly how to make an analogy for that. i don't know what to compare Nephrogenic diabetes insipidus to. please help

**Healthcare**

I agree with everything above....that is exactly how i feel! i have the same problems!

**Healthcare**

I agree with everything above....that is excatly how i feel! i have the same problems!

**ethics**

Things don't get fixed over night. Sounds like some people need to get a little more patience. Obama is doing a fine job.

**ethics**

Things down get fixed over night. Sounds like some people need to get a little more patience. Obama is doing a fine job.