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Chemistry Feedback

by Ron Kurtus

Each day readers send in questions and feedback concerning the various lessons in the School for Champions website. A total of 541 letters have been answered.

List of most recent 15 letters




Define Electronegativity matter Polar Molecules Ethiopia
About Nitrogen Uses of Nitrogen Philippines
Examples of liquid non-polar compounds Polar Molecules India
Why is oxygen classified as non-polar? Polar Molecules Namibia
Use of arrow sign in chemical reaction Chemical Equations India
Can I used compressed nitrogen to paint a boat? Uses of Nitrogen USA
Solids used to obtain oxygen gas Oxygen Kenya
How is CO2 non-polar? Polar Molecules Namibia
Questions for science project Uses of Nitrogen USA
Correction in formula Order of Elements in a Formula USA
Why do nonpolar solutes tend to adhere Polar Molecules China
Name the following compounds General Nigeria
Which is the lightest gas? Uses for Hydrogen Ghana
Is an apple a polar molecule? Polar Molecules Pakistan
Wants objective questions Chemistry Basics Pakistan

Next 15 letters

Polar Molecules

Define Electronegativity matter

December 6, 2016


Define Electron Negativity matter on polarity and non polarity

Fanuel - Ethiopia (27533)


Electronegativity is a measure of the tendency of an atom to attract a bonding pair of electrons. Using the Electronegativities we can predict whether a given bond will be non-polar, polar covalent, or ionic. The greater the difference in electronegativity the more polar the bond.

See Bond Polarity and Polar vs Non-Polar Molecules for more information.

I hope that helps

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Uses of Nitrogen

About Nitrogen

August 11, 2016


Nitrogen physical properties,origin,characteristics and uses?

Noel - Philippines (27203)


Read Nitrogen and Uses for Nitrogen.

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Polar Molecules

Examples of liquid non-polar compounds

July 10, 2016


Example of liquid non polar compounds.

Raman - India (27142)


Oils, including vegetable oil and related products like gasoline, are the most common examples of non-polar liquids.

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Polar Molecules

Why is oxygen classified as non-polar?

June 25, 2016


why oxgyen is classfied as non polar and carbon dioxide polar ?

Johannes - Namibia (27105)


Whether a molecule is polar or non-polar depends on its geometry. Oxygen exists as a molecule of two oxygen atoms. The combination balances the distribution of their electrons.

Carbon dioxide is also a non-polar gas for the same reason.

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Chemical Equations

Use of arrow sign in chemical reaction

May 16, 2016


Some of the chemical reactions are represented by arrow sign and some are by equal sign. What is the difference between this two types?

Kind Regards,

Mohammad - India (27008)


If the chemical reaction mainly goes in one direction, it is represented by an arrow to indication the direction. For example C + O2 --> CO2.

Some reactions can readily go in both directions and are represented by a double arrow ( <---> ) or an equals sign.

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Uses of Nitrogen

Can I used compressed nitrogen to paint a boat?

April 29, 2016


Hey there, I am Nelson from Nautiques Boat Care. My question is can I use it nitrogen as a substitute to regular air pressure when I spray the paint or gel coat to avoid moisture?

Jose - USA (26971)


Since air is made up of 80% nitrogen, using compressed nitrogen to spray the paint. Besides nitrogen and oxygen, air also includes water vapor.

However, compressed nitrogen probably would be more expensive than compressed.

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Solids used to obtain oxygen gas

April 27, 2016


Name two solids that can be heated to obtain oxygen gas.

Engneer - Kenya (26969)


Mercuric oxide (HgO), potassium chlorate (KClO3), and sodium peroxide (Na2O2)

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Polar Molecules

How is CO2 non-polar?

April 13, 2016


Why do we say Carbondioxide gas is a non-polar in terms of charges on it. It seems like oxygen has more electrons than carbon in gas. I am confused help me please.

Mweneni - Namibia (26927)


The atoms in carbon dioxide (CO2) are arranged in a line, with the oxygen atoms on the outside. This makes the distribution of charges symmetrical, making the gas molecules non-polar.

See the illustration of CO2 in Polar and Non-Polar Molecules. I hope that helps you understand the concept.

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Uses of Nitrogen

Questions for science project

April 9, 2016


Hi, my name is Jennifer. I am emailing you because this is for my science class project and my subject was on nitrogen. And just wondering if you could answer at least two questions for me. Q1: Is nitrogen good or bad for you? Q2: when was nitrogen discovered for these uses? Please answer ASAP, please and thank you. Thank you for your time to email this!

Jennifer - USA (26918)


Since nitrogen makes up about 78% of the air you breathe, it certainly is not bad for you. What makes it good for you is that it makes sure you don't get too much oxygen at once.

Nitrogen is a key component of biological molecules such as proteins (which are made from amino acids, and nucleic acids. The nitrogen cycle in nature is very important.

Nitrogen was discovered by Daniel Rutherford in 1772 at Scotland.

I hope that helps. Best wishes for success in your science project.

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Order of Elements in a Formula

Correction in formula

January 28, 2016


On your page regarding the order of elements in a chemical formula, you made the following statement:

"Most oxides will end in multiples of O, no matter what the alphabetical order. A good example is silicon dioxide: SO2"

However, I would just like to point out this (referring to the EXAMPLE) is wrong - I don't know if you are trying to refer to sulfur dioxide or SiO2. Just wanted to let you know so you could fix it! By the way, your page is amazing, super-informative and really helps me - thank you so much!

Shada - USA (26727)


Thanks for letting me know about that typo. I corrected the formula to be SiO2 in the Order of Elements in a Chemical Formula page.

I'm also glad the material has been useful to you.

Best wishes in your studies.

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Polar Molecules

Why do nonpolar solutes tend to adhere

January 9, 2016


I have a question
Explain why two nonpolar solutes (or nonpolar groups) tend to adhere to each other in aqueous solutions

qun - China (26673)


This is known as the hydrophobic effect, where nonpolar substances to aggregate in aqueous solution and exclude water molecules. This occurs because interactions between the hydrophobic molecules enable the displaced water molecules to make hydrogen bonds more freely with each other and increase the number of hydrogen bonds they are involved with, thereby decreasing the overall free energy.

I hope that answers your question.

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Name the following compounds

December 6, 2015


what is the Iupac name of the following compounds

Musa - Nigeria (26591)


I am sorry, but I do not have that information.

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Uses for Hydrogen

Which is the lightest gas?

December 2, 2015



YUNUSAH - Ghana (26586)


The Hydrogen molecule (H2) weighs 2 atomic units (AU), while the Helium atom is heavier and weighs 4 AU.

The problem is that Hydrogen is highly inflammable, thus Helium is usually used in balloons, because it does not burn and is safer.

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Polar Molecules

Is an apple a polar molecule?

October 23, 2015


Apple is polar molecule or non-polar molecule......?

M.Naveed - Pakistan (26468)


An apple is made up of many different types of molecules. Some may be polar and some non-polar.

If you select a specific molecule or material in an apple, you can find whether it is polar or not.

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Chemistry Basics

Wants objective questions

October 21, 2015


please kindly send me an objective type questions

haseeb - Pakistan (26462)


I'm sorry but the only questions we have right now are in the Mini-Quiz. However, there is a Graded Chemistry test you can take.

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Next 15 letters

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