Science & Mathematics - 31 October 2007

2007-10-31 07:43:51 · 7 answers · asked by Betdotman 1 in Astronomy & Space

A friend of mine told me that if the sun was the slightest bit closer to the Earth, it'd be too hot for anybody to live on, and if the sun was the slightest bit farther away from the Earth, it'd be too cold for anybody to live on . IS THIS TRUE ? I know the sun is closer to the Earth during the summer, so I'm suspicious . Does what my friend told me have any basis in fact, or was he mistaken ?

2007-10-31 07:42:22 · 13 answers · asked by I_hate_being_single 3 in Astronomy & Space

The length of one side of the base is 6in and the height of the pyramid is 11in.

2007-10-31 07:42:13 · 3 answers · asked by bristo75 1 in Mathematics

I am looking for a type of material that can change shape, contract, dialte when an electric pulse is pass through it either due to the voltage or the current. Please help, i need it for a project really soon.

2007-10-31 07:41:18 · 2 answers · asked by Prof.G 1 in Engineering

Ok I have these problems:

sec(7r/6)

and cot(5r/4)

and csc(7r/2)

to find these on a calculator do i just do..

sec= 1/cos(7r/6)
cot=1/tan(5r/4)
csc= 1/sin(7r/2)

2007-10-31 07:39:37 · 4 answers · asked by Anonymous in Mathematics

2007-10-31 07:35:45 · 2 answers · asked by Anonymous in Engineering

I mean like to filter the genetic feature of intelligence from the the subject's DNA..

2007-10-31 07:33:46 · 6 answers · asked by Ohad R 1 in Biology

A circle of unknown radius has a chord of length d whose midpoint is 1 foot from the circle. Find the radius, r, of the circle [in inches].
Please solve and give me compleate answer. I beliave there must be more than one answer please list all. THANKS!

2007-10-31 07:31:51 · 4 answers · asked by Anonymous in Mathematics

2007-10-31 07:31:18 · 4 answers · asked by Anonymous in Zoology

Hi, could you help me with this question and also explain the steps, thanks!

A uniform semicircular lamina is suspended from an end point of its diameter. Assuming that it hangs freely under gravity, calculate in radians the angle between the diameter and the vertical.

2007-10-31 07:30:12 · 1 answers · asked by clueless 1 in Physics

2007-10-31 07:27:39 · 2 answers · asked by tina d 1 in Mathematics

2007-10-31 07:26:31 · 2 answers · asked by John T 1 in Physics

2007-10-31 07:24:46 · 2 answers · asked by John T 1 in Physics

2007-10-31 07:24:35 · 7 answers · asked by joy o 1 in Mathematics

2007-10-31 07:23:32 · 4 answers · asked by John T 1 in Chemistry

Urgent ..Please help me :)

2007-10-31 07:23:24 · 3 answers · asked by Anonymous in Chemistry

2007-10-31 07:19:40 · 3 answers · asked by Anonymous in Astronomy & Space

2007-10-31 07:19:23 · 4 answers · asked by Anonymous in Zoology

2007-10-31 07:18:27 · 7 answers · asked by Anonymous in Astronomy & Space

2007-10-31 07:16:08 · 3 answers · asked by Anonymous in Physics

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2007-10-31 07:15:58 · 1 answers · asked by purple21 1 in Physics

CCl4, an important commercial solvent, is prepared by the reaction of Cl2(g) with a carbon compound. Determine H° for the following reaction.
CS2(l) + 3 Cl2(g) CCl4(l) + S2Cl2(l)

Use appropriate data from the following listing.


CS2(l) + 3 O2(g) CO2(g) + 2 SO2(g) H° = -1077 kJ
2 S(s) + Cl2(g) S2Cl2(l) H° = -58.2 kJ
C(s) + 2 Cl2(g) CCl4(l) H° = -135.4 kJ
S(s) + O2(g) SO2(g) H° = -296.8 kJ
SO2(g) + Cl2(g) So2Cl2(l) H° = +97.3 kJ
C(s) + O2(g) CO2(g) H° = -393.5 kJ
CCl4(l) + O2(g) COCl2(g) + Cl2O(g) H° = -5.2 kJ

2007-10-31 07:14:18 · 3 answers · asked by Anonymous in Chemistry

Determine H° for the following reaction.
N2H4(l) + 2 H2O2(l) N2(g) + 4 H2O(l)

You are given these data.


N2H4(l) + O2(g) N2(g) + 2 H2O(l) H° = -622.2 kJ
H2(g) + 1/2 O2(g) H2O(l) H° = -285.8 kJ
H2(g) + O2(g) H2O2(l) H° = -187.8 kJ

2007-10-31 07:13:51 · 1 answers · asked by Anonymous in Chemistry

help H3COCH3

i cant figure out the lewis structure for this one. i come up with a total of 26 dots

2007-10-31 07:13:41 · 2 answers · asked by nikkylyn 5 in Chemistry

You are given the following data.
H2(g) + 1/2 O2(g) H2O(l) H = -285.8 kJ
N2O5(g) + H2O(l) 2 HNO3(l) H = -76.6 kJ
1/2 N2(g) + 3/2 O2(g) + 1/2 H2(g) HNO3(l) H = -174.1 kJ

Calculate the H for the reaction given below.
2 N2(g) + 5 O2(g) 2 N2O5(g)

2007-10-31 07:13:31 · 1 answers · asked by Anonymous in Chemistry

Calculate w and E when one mole of a liquid is vaporized at its boiling point (71°C) and 1.00 atm pressure. Hvap for the liquid is 37.1 kJ mol-1 at 71°C.

2007-10-31 07:11:40 · 1 answers · asked by toocool 1 in Chemistry

Combustion of table sugar produces CO2(g) and H2O(l). When 1.92 g of table sugar is combusted in a constant volume (bomb) calorimeter, 31.56 kJ of heat is liberated.
(a) Assuming that table sugar is pure sucrose, C12H22O11(s), write the balance equation for the combustion reaction.

Calculate E in kJ/mol C12H22O(s) for the combustion of sucrose.


Calculate H in kJ/mol C12H22O(s) for the combustion of sucrose at 25°C.

2007-10-31 07:11:00 · 2 answers · asked by toocool 1 in Chemistry

A 134 g stainless steel ball bearing (sp ht = 0.50 J g-1 °C-1) at 525°C is dropped onto a large block of ice at 0°C, what mass of liquid water will form? (H°fusion = 6.01 kJ/mol H2O(s))

2007-10-31 07:10:09 · 1 answers · asked by toocool 1 in Chemistry

A 3.34 g sample of aluminum pellets (specific heat capacity = 0.89 J °C-1 g-1) and a 10.00 g sample of iron pellets (specific heat capacity = 0.45 J °C-1 g-1) are heated to 100.0°C. The mixture of hot iron and aluminum is then dropped into 95.2 g of water at 21.7°C. Calculate the final temperature of the metal and water mixture, assuming no heat loss to the surroundings.

2007-10-31 07:09:35 · 1 answers · asked by toocool 1 in Chemistry

find the following percentiles for standard normal random variable z:

a- 65th percentile
b- 20th percentile
c- 90th percentile
d- 50th percentile
e- 99th percentile

2007-10-31 07:07:44 · 3 answers · asked by bob b 1 in Mathematics