Hannah

A 2-foot tall dog is walking away from a streetlight which is on a 10-foot pole. At a certain moment, the tip of the dog's shadow is moving away from the streetlight at 5 feet per second. How fast is the dog walking at that moment?

Explain, please!

I went to a guys house yesterday, and he really likes me. We kissed a few times and cuddled, but I have no feelings for him. I'd like to hook up, but I don;t want to lead him on anymore. What should I do?

1. The line L1 may be represented by r=(3,-3,8)+s(1,-2,3)

a.) What information does vector (1,-2,3) give about L1?

My answer: (3,-3,8) and (3,-3,8)+(1,-2,3)=(4,-5,11) are both points in a plane through which the same vector passes.

Is this correct? If not, please explain!!

b.) The point T (-1,5,p) lies on L1. Find the value of p.

I know I need to multiply something by (-1,5,p), set it to 0, and solve for p, but what do I multiply it by?

Thank you so much! Please show work and help me understand!

The following mechanism has been proposed for this reaction:

H2O2+ I– → IO– H2O

H2O2 + IO– → I– + H2O + O2

If this mechanism is correct, which step must be the rate-determining step? Explain.

Name all the aldehydes and ketones that have the formula C5H10O. (Enter your answers for each column in alphabetical, then numerical order.)

There are 4 aldehydes, I got:

____

2-methylbutanal

3-methylbutanal

____

and 3 ketones

i got:

____

2-pentanone

3-pentanone

Provide a plausible explanation as to why spectral lines within the visible spectrum are not able to be seen.

This is for an AP Chemistry lab... the violet value for the H could not be seen. Why? Does something aborb it before it reaches the eyepiece? I have no idea?

Find the height and radius dimensions that will give the least amount of surface area for a cylinder. How do I set this up?

Help! Please explain.

Help!

You are given the following data.

P4(s) + 6 Cl2(g) 4 PCl3(g) ΔH = -1225.6 kJ

P4(s) + 5 O2(g) P4O10(s) ΔH = -2967.3 kJ

PCl3(g) + Cl2(g) PCl5(g) ΔH = -84.2 kJ

PCl3(g) + 1/2 O2(g) Cl3PO(g) ΔH = -285.7 kJ

Calculate ΔH for the following reaction.

P4O10(s) + 6 PCl5(g) 10 Cl3PO(g)

I get -610.1 kJ and WebAssign says to check sig figs. Can anyone help and explain?

I know KE= 1/2mv2

I keep getting 3.0 J which is wrong. Please explain!!

This is for a lab . . . I have no clue how to do it.

Find the speed at which you threw the ball knowing only the time in the air. Time in air: 3 seconds.

A=-4.9m/s2

b=initial velocity/speed.

c=initial height

Here's where I'm confused: we're assuming the initial height is 0. And the initial velocity, too? So that means we're just left w/ A–– h(t)=-4.9m/s2(3^2)=-44.1

And that doesn't make sense. PLEASE help!

Helium is collected over water at 25°C and 1.00 atm total pressure. What total volume of gas must be collected to obtain 0.519 g of helium? (At 25°C the vapor pressure of water is 23.8 torr.)

A solution was prepared by mixing 49.00 mL of 0.100 M HNO3 and 137.00 mL of 0.210 M HNO3. Calculate the molarity of the final solution of nitric acid

Please explain!

An isosceles triangle ABC has two side lengths measuring 4cm and a variable altitude. Let altitude be denoted by x.

Find, in terms of x, a relation for

i. its perimeter, p(x) cm and specify its implied domain

ii. its area, A(x) cm^2 and specify its implied domain

Please work out/explain! And don't worry about the domains––I know how to find those.

Thank you so much!

Consider the following unbalanced reaction.

P4(s) + F2(g) --> PF3(g)

What mass of F2 is needed to produce 104 g of PF3 if the reaction has a 84.1% yield?

Here's what I got...it's wrong.

P4 + 6F2 --> 4PF3

it came out to 79.107 g F2, which is off.

Please work out and explain!

What mass of phosphorus is present in 5.06 mol of each of the compounds listed?

P4O6

Ca3(PO4)2

Na2HPO4

Please work through them and EXPLAIN!!

Thank you so much!

From the information in this chapter on the mass of the proton, the mass of the electron, and the sizes of the nucleus and the atom, calculate the density of a hydrogen nucleus. (Radius of a hydrogen proton is 5. x10^-14 cm)

Answer in g/cm^3.

Proton: 1.673x10^-27 kg

I asked this before, but I keep getting it wrong!!! I'm getting 3.2x10^15 g/cm^3.

Please work it out, and use the correct number of sig figs!!!

THANKS!

From the information in this chapter on the mass of the proton, the mass of the electron, and the sizes of the nucleus and the atom, calculate the densities of a hydrogen nucleus. (Radius of a hydrogen proton is 5. x10^-14 cm)

Answer in g/cm^3.

Proton: 1.673x10^-27 kg

Please explain!