Forums / Fun! / Just For Fun

so i failed statistics (passed it the second time) and failed general chemistry 1 for my freshman year of college, and i'm telling you some of those questions were fucking impossible, so here goes some and i hope you can answer some of them

Assume that the weights of all packages of a certain brand of cookies are normally distributed with a mean of 32 ounces and a standard deviation of 0.3 ounces. Determine the probability that the mean weight of a random sample of 20 packages of this brand of cookies will be:
(a) Between 31.8 and 31.9 ounces

so what are my other choices?

If 250. L of nitrogen reacts with 582 L of hydrogen by the reaction:
N2 + 3H2 (g)→ 2NH3(g)
how much nitrogen is unreacted ? All gases are at the same temperature and pressure

Suppose there are 106 body temperatures having a mean of 98.20 F. Assume that the sample is an SRS and the population standard deviation is known to be 0.62 F. Use a 0.05 significance level to test the common belief that the mean body temperature of healthy adults is equal to 98.6.
and
A study conducted a few years ago claims that the adult males spend an average of 11 hours a week watching sports on television. A recent sample of 100 adult males showed that the mean time they spend per week watching sports on television is 9.50 hours with a standard deviation of 2.2 hours.

(a) Test at the 5% significance level if currently all adult males spend less than 11
hours watching sports on television.

If 250. L of nitrogen reacts with 582 L of hydrogen by the reaction:
N2 + 3H2 (g)→ 2NH3(g)
how much nitrogen is unreacted ? All gases are at the same temperature and pressure

First we need to know how much moles we have of each substance.

• There is 250 L of Nitrogen. The density of Nitrogen is 1.251 g/L. This gives the Nitrogen a mass of (250 * 1.251 =) 312.75 grams. The molecular weight of N2 is (14.007 * 2 =) 28.014. This makes the amount of Nitrogen (312.75 / 28.014 =) 11.164 moles.
• There is 582 L of Hydrogen. The density of Hydrogen is 0.08988 g/L. This gives the Hydrogen a mass of (582 * 0.08988 =) 52.31016. The molecular weight is (1.008 * 2 =) 2.016. This makes the amount of Hydrogen (52.31016 / 2.016 =) 25.9475 moles.

Now that we know that, you already gave us the reaction:
N2 + 3H2 (g)→ 2NH3(g)

So the gasses react in a proportion of 1:3. We know that all the Hydrogen will react. With 25.9475 moles of Hydrogen, we'll have (25.9475 / 3 =) 8.6492 moles of Nitrogen react. This leaves us with (11.164 – 8.6492 =) 2.5148 moles of Nitrogen.

Now calculate back:
2.5148 * 2.016 = 5.0698 grams
5.0698 / 1.251 = 4.0526 Liters

So 4.05 Liters of Nitrogen is unreacted.

This is math = 2 + 2 equals 4

This is math…on drugs = Everything up there

The complete combustion of propane, C3H8, is represented by the equation:
C3H8 + 5O2(g) →3CO2(g) + 4H2O(l) ΔH= -2220 kj
How much heat is evolved in the complete combustion of 20.0 L C3H8 at STP?

48÷2(9+3) = ?

• The density of propane is 2.0098 mg/mL. You have 20.0 L, which is 20,000 mL.
  • 20,000 * 2.0098 = 40,196 mg, which is 40.196 grams.
• The molar mass of propane is 44.10 g/mol. You have 40.196 grams.
  • 40.196 / 44.10 = 0.91147 mol.

ΔH= -2220 kj/mol

2220 kJ/mol * 0.91147 mol = 2023.4721 kJ

So 2023.47 kJ.

In this hydrogen atom how much energy is required to remove one mole of electrons from the n=4000 energy level? What is the frequency of this EM? What is the wavelength of this EM?
__________________________________________________________________________________

How much energy is released from one mole of electrons when they relax from n=5 to n=2? What is the wavelength and color of this emission?
__________________________________________________________________________________

The wavelength of a certain blue light is 430 nm. Express this wavelength in meters. Calculate the frequency of this blue light. Calculate the energy of one photon of this blue light. Calculate the energy of one mole of photons of the blue light?

Quick question, are you like in any sort of science field or do you just know a lot about chemistry

Oh come on, man. You promised math in this thread, and you're giving us physics and chemistry. I have to admit, I feel a bit let down.

Now, here's some goddamn math for everybody:
Find the exact value of ∫(0 to π/4)sec^3(x)dx

its still math, its just the variables are chemicals.

I suppose you're technically right. However, it's not pure math, and I'm a math purist. I'm serious, I'm fucking OCD about math.
…
Okay, maybe I'm not serious, but…
…what were we talking about again?

If you want to pass college chemistry without being good as math, you might as well spread your cheeks and invite the teacher.

SOLVE THIS:

Oh! Wait, I thought of a better one!

YES! TWO PLUS TWO! Solve it or die~

"Uh, 4?"

HAH, HAH, HAH, HAH.

Z scores are the distance from the mean divided by the standard deviation.

So, the limiting z scores are -0.666 and -0.333, respectively.

A distribution table table tells us that .24563 of the normally distributed values should be below z = -0.66 and .37070 of the of the values fall below -0.33.

.37070
- .24563
---------------
0.12507

or, 12.507% of the cookies fall between 31.8 and 31.9 ounces.