Chemistry

This category encompasses all questions about the composition, structure, properties, and reactions of matter.

Industrial Engineering
Physics
Chemistry

Is the electrical resistance intensive or extensive?

Resistance is extensive - it depends on shape and size as well as resistivity (the intensive property)

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Physics
Chemistry

What happens to the temperature of naphthalene during melting?

Lab: Melting / Freezing Point of NaphthaleneObjective: In this lab, you will investigate the melting and freezing point of the substance, naphthalene (moth ball flakes). You will heat solid naphthalene and record temperature changes and examine the graph to determine the melting point of the substance. You will then cool naphthalene and record temperature changes in order to determine the Freezing point of the substance

Part A: What happens to temperature as naphthalene melts?

Objective: As heat is applied to liquid naphthalene, the temperature rises. As the temperature rises, the naphthalene will eventually start to melt. This lab experiment tries to answer the question: what happens to the temperature of naphthalene as it melts? In this lab, you will heat the liquid naphthalene, and record the temperature changes. You will graph the temperature changes before drawing any conclusions.

Part B: Determining the freezing point of naphthaleneObjective: Freezing point is a characteristic property of matter. As heat is taken away from a liquid, the temperature of that liquid decreases as the substance begins to freeze. This lab experiment tries to answer the question: what is the freezing point of an unknown liquid (naphthalene)? In this lab, you will cool liquid naphthalene, and record the temperature changes. You will graph the temperature changes before drawing any conclusions.
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Science
Chemistry

Boiling waters idepended variable?

No, an independent variable is something that changes in an experiment.

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Chemistry

Which functional group does the molecule below have?

An Which functional group does the molecule below have?

A. Carbonyl B. Ether C. Hydroxyl D. Amino swer this question…
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Chemistry

Why is chemistry is considered as an art and science?

a compund cannot ve btroken down yb phsuicka methosds it is made up or different cholridn niacn dieflakf iehiheiyriediyiui iuimaind

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Physics
Chemistry

What energy transformation occurs when you ring a bell?

Energy can not transform.

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Chemistry

Does the line spectrum of water vapor bear any resemblance to the line spectra of hydrogen and oxygen?

Yes there will be. This is because when you take line spectrum of water vapor, then hydrogen and oxygen atoms will form their own line spectra and the final spectrum will be a combination of the two.

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Chemistry

A combination reaction occurs when one reactant forms two or more products.?

false

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Chemistry

What are two physical characteristics of ionic compounds What is one chemical characteristics of ionic compounds?

Ionic compounds are hard and rigid due to strong forces of attraction between the oppositely charged ions. Ionic compounds have high melting and boiling points, again due to strong forces of attraction between the ions. Ionic compounds dissolve easily in water.

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Chemistry

What is the disadvantage of chemical test?

Any disadvantage if the test is serious.

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Chemistry

Explain the similarities and differences in the formation shown in a molecular formula and a structural formula for the same substance?

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Science
Chemistry
Periodic Table

What is the fourth element of the periodic table of elements?

Beryllium (Be)

See the Web Links and the Related Questions for more information.

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Chemistry
Periodic Table
Atoms and Atomic Structure

What type of element is a protactinium?

A highly radioactive metal and weakly basic actinide.

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Science
Chemistry
Acids and Bases

What are some examples of chemical and physical changes?

Physical Changes

  • Change of state (such as from solid to liquid or from gas to liquid)
    • Specific examples of state change include water freezing, alcohol evaporating and dry ice (solid carbon dioxide) subliming
  • Absorption of water into a towel
  • Crumpling a piece of paper
  • Pulling copper into a thin wire - a change of shape, but not a change of composition
  • Cutting a material such as wood
  • Tearing a piece of tin foil
  • Breaking glass
  • Deflating a basketball
  • Mixing different solids (such as solid sulfur and iron filings)
  • Inflating a volleyball
  • Cloud forming in the sky

Chemical changes

  • Burning a log of wood
  • Mixing an acid with a base, producing water and a salt.
  • Photosynthesis - a process in which carbon dioxide and water are changed into sugars by plants.
  • Cracking heavy hydrocarbons to create lighter hydrocarbons (part of the process of refining oil).
  • Cooking examples: popcorn, cake, pancakes, and eggs
  • Oxidation examples: rust or tarnishing
  • Combustion
  • Mixing chemicals
  • Rotting of fruit
  • Cooking rice
  • Explosion of fireworks
  • Tarnishing silver
  • Lighting a match
  • Chewing/digesting food
  • Rusting nail
  • Burning gas in a stove
  • Oxidizing food for energy
  • Roasting a marshmallow
  • Adding food coloring to icing
  • Frying an egg
  • Burning a magnesium strip

The following can indicate that a chemical change took place, although this evidence is not conclusive:

  • Change of color (for example, silver to reddish-brown when iron rusts)
  • Change in temperature or energy, such as the production (exothermic) or loss (endothermic) of heat
  • Change of form (for example, burning paper)
  • Light, heat, or sound is given off
  • Formation of gases, often appearing as bubbles
  • Formation of precipitate (insoluble particles)
  • The decomposition of organic matter (for example, rotting food)
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Chemistry
Atoms and Atomic Structure
Chemical Bonding

How do you determine if a molecule is polar or non-polar?

Polar Bonds and Molecular Shape

A polar molecule is a molecule that has a net dipole moment due to its having unsymmetrical polar bonds. There are two factors that go into determining if a molecule is polar or not. To determine if a molecule (or ion) is polar or non-polar, you must determine both factors.

  • The polarity of the individual bonds in the molecule.
  • The shape or geometry of the molecule.

First, to determine if a given individual bond is polar, you need to know the electronegativity of the two atoms involved in that bond. To find the electronegativities of all the elements, look at the periodic table (follow the link below this answer under Web Links).

If the electronegativity of the two atoms has a difference of 0.3 or less, then the bond is non-polar. If the electronegativity difference is greater that 0.3 but less than 1.7, then the bond is polar. If the two values have a difference greater than 1.7, then the bond is ionic, which is just very very polar.

Once you know which bonds in the molecule are polar and which are non-polar, you must use the shape of the molecule. You need the shape because two polar bonds, if oriented correctly can cancel each other out (like two equally strong people pulling in opposite directions on a rope -- nobody moves).

The three possible outcomes:

  • If all bonds are non-polar, then the whole molecule is non-polar regardless of its shape.
  • If there is symmetry in the molecule so that the polarity of the bonds cancels out, then the molecule is non-polar. A common example of this is carbon dioxide, or CO2. The molecule is linear, and its Lewis dot structure is like this: O=C=O (this doesn't include two sets of lone pairs on each oxygen). The carbon-oxygen bond is a polar bond, but because they are exactly opposed to each other, the molecule is overall non-polar. Another example of this is CCl4, where each carbon-chlorine bond is polar, but the molecule is non-polar. Here, how they cancel out isn't as obvious, but they do. CCl4 is a tetrahedral molecule, and the 4 C-Cl polar bonds cancel each other out.
  • If there are polar bonds but there is no symmetry such that they cancel each other out, the overall molecule is polar. Water is a typical example of this. The two O-H bonds are oriented in a V-shape, and so the don't cancel out. Similarly, CH3Cl is also polar. It is the same shape as CCl4 (see above), but now it doesn't have the same symmetry because there is only one C-Cl bond and the bonds don't cancel out anymore.
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Math and Arithmetic
Chemistry
Statistics
Percentages, Fractions, and Decimal Values

What is the percent error formula?

Percent Error is the difference between the true value and the estimate divided by the true value and the result is multiplied by 100 to make it a percentage. The percent error obviously can be positive or negative; however, some prefer taking the absolute value of the difference.

The formula is the absolute value of the experimental value (minus) the theoretical value divided by theoretical value times 100.

% error = (|Your Result - Accepted Value| / Accepted Value) x 100

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Biology
Physics
Chemistry

Which science is the most complex chemistry or biology or physics?

biology because it tells us what is important to humans and biology is more easier than physics and chemistry

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Science
Chemistry

10 examples of physical change and chemical change?

Physical Change:

*Milo dissolves into hot milk

*A plate is dropped and shatters

*Grass in mowed

*Metal Knife is sharpened

*Breakfast Cereal goes soggy

Chemical Change:

*Wood burns to form black charcoal

* A green tomato ripens and turns red

* Fireworks explode to form colourful light and loud sounds

* Vegetables scraps in the compost bin decompose to form rich soil

* An egg is cooked to become a white and yellow solid

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Chemistry
Gold and Precious Metals

What is the formula of white gold?

Well,white gold never existed, but any industry to create the best white gold formula alloys is the one go to make big money. Because the consumer is looking for the best precious metal alloys; any person that has his or her own real pure solid white gold formula alloys, is not in their best interest to specify the formula to any other person. In this world we have more that 181 precious metals to combine to produce your own white gold formula; you only make sure when you find the formula that pass the acid,and magnet test, you can make jewelry to not loose the white color for life. Yellow gold with Rhodium is not real pure color white gold. You do not need yellow gold to create the karat 10k threw 21k to past the acid and magnet test.With all the problem to create yellow gold with Rhodium the jewelry industry, lied to the consumers that it is white gold when its not. Now we have to guaranty the pure solid white gold formula alloys for life time, or money back guaranty! Think good Wake Up. Real pure solid white gold formula alloys precious metals is the best to create white gold, and that it is not yellow gold alloys with Rhodium. Sincerely, see web page. Living Life Enterprises Presents. For the best interest to the consumers.

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Chemistry

Does water and spirit get mixed together?

no it does not but there is said that there is a "spirit"that guards a lake or waterfall there was one picture with a water spirit in it they do not mix the lake they love and died in maybe why people say that there is water spirits believe it or not I'm only 10

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Chemistry
Law & Legal Issues

What gas law applies to aerosol cans being stored in a cool place?

Newton's 3th

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Cleaning
Chemistry
Manicures and Pedicures

How do you remove nail polish stains from your carpet?

Dab a little bit of nail polish remover on the carpet and let it sit. After a while spray some kids and pets spray on the spot then dab some more nail polish remover. Let it sit again and go back and scrub with a cotton ball dipped in nail polish remover.
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Chemistry
Civil Engineering
Construction
Metallurgy

What does Fe500 steel mean?

The abbreviation

Fe stands for Ferrous material ie iron from which the reinforcement steel bars are manufactured.

The reinforcement steel bars used in RCC (Reinforced Cement Concrete) are designated as Fe415 or Fe500 depending on their Yield Strength. (The numbers 415 and 500 tell about this Yield Strength in N/mm2 the bars are designed and manufactured to have.)

As per IS : 1786 Yield Stress (also known as 0.2%proof stress) of Fe 500 is 500 N/mm2.

So, Fe500 steel means the reinforcement steel rods (or bars) that can safely withstand an Yield Stress of 500 N/mm2.

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Chemistry
Philippines

Who are some famous Filipino chemists and what are their contributions to the field of chemistry?

Filipino Chemists and their contributions

Julian Banzon - experimented with the production of ethyl ester fuels from sugarcane and coconut and invented a means of extracting residual coconut oil by a chemical process rather than a physical process. A pioneer for alternative fuels ROM the 1930's and 40's.

Francisco Quisumbing - invented Quink ink (currently used in Parker Pens) which is a quick drying ink that prevents the ink from clogging the pen.

Ramon Barba - created crop flowering techniques using a potassium nitrate spray. Due to his discoveries in tropical tree physiology, the Philippines is the leading exporter of mangoes and mango products.

Francisco Santos - studied the nutritive values and chemical composition of local foods from the Philippines. His data was used to help detect and solve problems with Filipino diets.

Rolando De La Cruz - inventor of an anti-cancer skin cream.

Anacleto Del Rosario - Winner of first prize at the World Fair in Paris in 1881 for for producing a pure alcohol from tuba of a nipa palm. His research also led to the process of extracting castor oil from a native plant called palma christi.

Alfredo Santos - isolation and elucidation of biochemicals (the phaeantharine and other alkaloids) from Philippine medical plants.

Eduardo San Juan - worked on the team that invented and launched the Lunar Rover (Moon Bugg)

Daniel Dingel - possible invention of a water-powered car

Benjamin Almeda - designed a cutting edge food-processing machine

More Filipino Scientists that have contributed to the field of chemistry:

  1. Lourdes J. Cruz
  2. Dr. Beatrice Guevara
  3. Dr. Evelyn Mae T. Mendoza
  4. Dr. Elma C. Llaguno
  5. Lani Rose Mateo
  6. Richard Sucgang
  7. Angel Arguelles
  8. Julian Bazon
  9. Luz Oliveros-Belardo
  10. Alfredo Santos
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Science
Physics
Chemistry
Chemical Bonding

Why does water have a high and specific heat capacity?

First, we need to know a little bit about water. Water is a polar molecule because oxygen bears partial negative charge and hydrogen bears partial positive charge. This results in extensive hydrogen bonding in water molecules between slightly negative oxygens and slightly positive hydrogens. Second, we need to remember that temperature is another way of saying the average kinetic energy of particles - the higher the temperature, the faster they move, in the case of gases and liquids, or vibrate, in the case of solids. Third, heat capacity is the ability of matter to absorb thermal energy. One calorie is defined as the amount required to heat a gram of water one degree Centigrade. That same calorie will heat a gram of gold 33 degrees.

Water's specific heat is defined as 1. The specific heat of gold is therefore .03. Water has a high specific heat because there are quite a few ways water can store heat. 1. Moving along three axes 2. Rotating the "V" shaped molecule in three different directions 3. Hydrogen atoms vibrating back and forth like a tuning fork 4. Hydrogen atoms vibrating up and down along their H-O axis.

Finally, the heat of fusion of water is 80 calories per gram, and the heat of vaporization for water is 540 calories. So ice can absorb 80 times as much heat while melting as the same mass of water. Water absorbs 540 times as much heat while turning into water vapor as the same mass of water absorbs. Both phase changes occur at constant temperature, 0 Centigrade and 100 Centigrade respectively. Look up phase change graph for water to see the interesting line.

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