Chemistry - February 2007

I'm thinking it's ethanol because it can form hydrogen bonds and is a good solvent, but I'm not sure. Please help! Thank you!

2007-02-08 09:50:15 · 4 answers · asked by smitty 1

When a substrate that is catalyzed by an enzyme is present in high concentrations, the effect on the rate of a reaction by changeing the substrate concentration can be described using zeroth-order kinetics. If the concentration of a such a substrate is changed from 2.09 × 10−3 M to 4.01 × 10−1 M, by what factor does the rate of the reaction change ?



That is rate (4.01e-1M) = f × rate (2.09e-3M)

what is the vaule of f ?

2007-02-08 09:47:44 · 2 answers · asked by joy 1

When enzymes are present in very low concentrations, their effect on the rate of a reaction can be described using first-order kinetics. If the concentration of a catalyzing enzyme is changed from 3.11 × 10−3 M to 5.03 × 10−1 M, by what factor does the rate of the reaction change ?

2007-02-08 09:47:16 · 2 answers · asked by joy 1

This question is about a practical lesson about gravimetric analysis. Please help I can't find it.

2007-02-08 09:43:49 · 1 answers · asked by Habiibti 1

In one beaker, 5.0 g of Mg powder is added to 250. ml of 1.0 M HCl acid. In a second beaker, 5.0 g of Mg powder is added to 250. ml of 0.5 M HCl acid. Which beaker would have the faster reaction rate? The reaction is:

Mg + HCl --> MgCl2 + H2

2007-02-08 09:43:43 · 1 answers · asked by jenn ayr 2

how was the element chlorine discovered?

2007-02-08 09:41:48 · 3 answers · asked by Anonymous

Can someone tell me what the balanced equation is for adding KMnO4 to sodium peroxoborate with HCl in it. What about the balanced equation for adding KI to Sodium peroxoborate with HCl in it.

2007-02-08 09:33:35 · 2 answers · asked by Anonymous

2007-02-08 09:33:23 · 1 answers · asked by Lakashia T 1

2007-02-08 09:22:16 · 3 answers · asked by Anonymous

A very blonde question. How in chemistry do things react, and why aren’t materials reacting all the time, for instance when you place potassium in water it reacts but why doesn't it react with the air. An answer explaining ions, atoms (protons and electrons) would be appreciated.

2007-02-08 08:56:01 · 6 answers · asked by Lora 2

I need to complete this stoichiometry question:

BASED ON THE AMOUNT OF GASOLINE (GALLONS) YOU USE IN A TYPICAL WEEK, HOW MANY KILOGRAMS OF CARBON DIOXIDE GAS DO YOU CONTRIBUTE TO THE ATMOSPHERE/WEEK?



Hints to help with the problem,
household uses 24.6 gallons/week,

90% of gasoline if Isooctane, C8H18,

10% of gasoline is Ethanol, C2H5OH,

density of isooctane is 0.703 g/mol,

density of ethanol is 0.789 g/mol,

molar mass of isooctane is 114.26,

molar mass of ethanol is 46.08,

molar mass of carbon dioxide is 44.01,

USE THESE COMBUSTION REACTIONS:
2C8H18 + 25O2 ---> 16CO2 + 18H2O is isooctane,

C2H5OH + 2O2 ----> 2CO2 + 3H2O is ethanol,

1 US Gallon is 3.785412 liters,

1 Cm (cubed) = 1 mL,

1L = 1000 cm (Cubed),

1 kg = 1000 g (mass),

2007-02-08 08:50:21 · 2 answers · asked by mebhoopz 2

okay so i have this homeowrk and its on multiple step conversions. i already know how to do the one step and i already know how to do all the other conversions. im stuck on the multiple step conversions. how do i know which measurement is which? say for example i have

convert 452 Millameters to Kilometers.
would i go..millameters to meters to kilometers? ugh im in serious help i have a test tomorrow. :(

2007-02-08 08:38:13 · 3 answers · asked by missunderstood 2

Aircraft use kerosene as fuel and it is also used as heating and lighting fuel the world over.

2007-02-08 08:02:51 · 7 answers · asked by Barrie G 3

If i wish to bind oxygen to a liquid, what liquid shoud i use?
If i wish to bind co2 to a liquid ,what liquid shoud i use?
(sorry for my sucky english)

2007-02-08 08:02:37 · 4 answers · asked by fredrik r 1

2007-02-08 08:00:02 · 2 answers · asked by Tracy Z 1

If a 0.120 mole sample CHO has a mass of 13.93 g .
what is the molecular formula of this compound?
41.39 % C

3.47 % H

55.14 % O

2007-02-08 07:57:20 · 6 answers · asked by Anonymous

Okay, i am doing a science project on chemical reactions inside a home setting. I have baking a cake as one .. because of odor change, color change, new substances form, ect. why is perming your hair one besides chemicals reacting to form new curls? and can anyone give me another example of a chemical reaction inside your home?

thanks ;]

2007-02-08 07:55:03 · 4 answers · asked by Anonymous

I have recently purchased 7kg of calcium chloide fro a science experiment, but after calculating it's density I found that it is the dihydrate form!

I suspect that like with most salts it can be dehydrated with external heat, is this true? Also how much? (just the temperature or if you know it the calories/mole)

Also at the moment I do not have access to a suitable vaccuum pump, so that is not an option.

Please no links to wiki

2007-02-08 07:24:20 · 3 answers · asked by Anonymous

2007-02-08 07:23:38 · 1 answers · asked by Anonymous

must be placed before hydrogen.
so question is what to write after coefficient!
need correct answer please!

2007-02-08 06:56:15 · 2 answers · asked by mahy 1

what functional group does triacylglycerol belong to?

2007-02-08 06:50:03 · 3 answers · asked by Anonymous

Petroleum is a mixture of hydrocarbons of various sizes. Oil refineries separate and collect these molecules into these different groups:

Refinery gas is a mixture of methane (CH4), ethane (C2H6), propane (C3H8) and butane (C4H10).
Gasoline is a mix of hydrocarbons containing 5 to 8 carbons (and their associated hydrogens).

Kerosene (sometimes called paraffin oil) is a mix of hydrocarbons containing 11 to 12 carbons (and their associated hydrogens).
Diesel oil (sometimes called gas oil) is a mix of hydrocarbons containing 13 to 25 carbons (and their associated hydrogens).

How do you think they are separated in oil refineries? How can refineries use temperature to separate petroleum into these groups?

2007-02-08 06:35:35 · 3 answers · asked by Mysara e 2

Q.1 How do the test on known solutions containing cations and anions make it possible for you to identify the cations or anions in an unknown substance?

Q.2 You have a solution that is composed of either NaCl or Cacl2. What test would you run to identify the compund?

Q.3 If tap water turns a deep red color with a few drops of KSCN, what cation is present?

Q.4 A plant food contains (NH4)3PO4. What tests would you run to vertify the presence of the NH4^+ ion and the PO4^3- ion?

Q.5 Write the symbol of the cation or anion that give(s) the following reaction:
1. Forms a precipitate with AgNO3 that does not dissolve in HNO3
2. Forms a gas with HCl
3. Gives a bright, yellow-orange flame test
4. Forms a precipitate with BaCl2 that does not dissolve in HNO3

2007-02-08 06:35:26 · 4 answers · asked by shortydidi03 2

2007-02-08 06:24:29 · 3 answers · asked by cutelagayguy 4

An aqueous ethanol solution (400 mL) was diluted to 4.00 L, giving a concentration of 0.0400 M. What is the concentration of the original solution?

2007-02-08 06:23:55 · 3 answers · asked by Anonymous

What is the concentration (M) of NaOH in a solution made by mixing 25.0 mL of 0.100 M NaOH with 50.0 mL of 0.100 M NaOH?

2007-02-08 06:20:47 · 4 answers · asked by Alan l 1

How many moles of N2 are produced by the decomposition of 2.88 mol of sodium azide?

2NaN3 (s) ---> 2Na (s) + 3N2 (g)

A) 1.44 B) 4.32 C) 8.64 D) .960 E) 1.92

My friend has a test and is stuck on this practice question. Please walk us through answer. Thank you!!

2007-02-08 06:12:21 · 4 answers · asked by Shanna T 1

I am doing this for a science experiment and need to know this for my hypothesis.

2007-02-08 06:11:03 · 5 answers · asked by amy 1

im just revising on past papers and this came up, im guessing that iodine has induced dipolar forces but what has chlorine got? it must have weaker forces to be a gas ????? im stuck please some lovely chemist help!!

2007-02-08 05:57:43 · 5 answers · asked by Jess-Ica 1

In a certain experiment the decomposition of hydrogen iodide on finely divided gold is zeroth order with respect to HI.
2HI(g) --AU-> H2(g) + I2(g)

Rate = -d[HI]/dt = k = 2.00×10-4 mol L-1 s-1

If the experiment has an initial HI concentration of 0.270 mol/L, what is the concentration of HI after 15.0 minutes?


How long will it take for all of the HI to decompose?


What is the rate of formation of H2 9.0 minutes after the reaction is initiated?


God I hate kenetics, please help.

2007-02-08 04:43:33 · 1 answers · asked by Anonymous