CHEMISTRY HIGH SCHOOL

Define physical change and chemical change and give examples of each type of change

Answers

Answer 1
Answer: Physical change does not change the composition of the substance for example: water to ice, evaporation of gasoline

Chemical change does change the composition of the substance for example: leaves changing color in fall, when you burn wood or gasoline

Related Questions

The percent composition by mass of certain compound is 35.5 percent carbon, 4.8 percent hydrogen, 37.9 percent oxygen, 8.3 percent nitrogen, and 13.5 percent sodium. What is the molecular formula if the molar mass is roughly 170 grams per mole
Help me pleaseeee!!!
How many atoms of carbon are in the sample
What is the chemical formula for zinc carbonate?(1) ZnCO3(2) Zn(CO3)2(3) Zn2CO3(4) Zn3CO3
Which formula represents copper(I) oxide?(1) CuO (3) Cu2O(2) CuO2 (4) Cu2O2

What two-step process separated the cans into aluminum, steel, and tin?

Answers

Answer:

Magnet

Durability and heaviness.(texture)

Explanation:

Magnet can be use to separate Aluminum from mixture of steel and aluminum.

Though aluminum and steel look alike but magnet can be use to separate it.

If the can attract the magnet or magnet stick to the can, it is a steel can. Aluminum does not stick to magnet.

A mixture of Aluminum and tin can also be separated by magnet.

Tin attract magnet but tin is more durable, heavy and does not corrode easily.

When u touch the three cans, tin is heavy and durable.

According to reference table J, which of these metals would react most readily with 1.0 M HCl to produce H2(g)

Answers

K is more reductor then CA then Mg then Zn

Burning alcohol for fuel is a very efficient process. Please select the best answer from the choices provideda. True
b. False

Answers

Explanation:

Burning of alcohol produces different products as it depends on the type and nature of alcohol which is being burnt.

Some alcohols upon burning produce toxic gases or products whereas some alcohols on burning does not produce any toxic substances.

For example, when ethanol is burnt then it reacts with oxygen and results in the formation of water and carbon dioxide.

Thus, we can conclude that the statement burning alcohol for fuel is a very efficient process is a false statement.  

Burning alcohol for fuel has been used throughout history. There are some alcohols that are the best ones to use as fuels because of their nature and can be synthesized chemicaly or biologicaly. Except, some of those alcohol also has a bad effect when burned for fuel as it would cause serious negative chemical effects when exposed to the human body such as blindness or death. Therefore, the best answer would be False.

Which of these compounds has chemical properties most similar to the chemical properties of ethanoic acid?(1) C3H7COOH (3) C2H5COOC2H5(2) C2H5OH (4) C2H5OC2H5

Answers

The correct answer is : (1) C3H7COOH.

Ethanoic acid has the molecular formula CH3COOH. It belongs to the homologous series of alkanoic acid or carboxylic acid. Homologous series are series of organic compounds in which a member differs from the next member by –CH2. One of the major characteristics of the homologues is their similarity in chemical properties. Propanoic acid (C3H7COOH) is the only member of the alkanoic acid family among the options given. So, it is the only one that has similar chemical properties with ethanoic acid.The other options are wrong because:

(2) C2H5OH belongs to the alcohol family.

(3) C2H5COOC2H5 belongs to the alkanoates family (esters)

(4) C2H5OC2H5 belongs to the ether family.
You need to first consider the properties of ethanoic acid that are worth noting. Ethanoic acid is a weak acid (the carboxyl group has a resonance-stabilized base), and the length of its carbon chain (2 carbons) reflects the strength of its Van der Waals forces. Also, the hydroxyl group (as part of the carboxyl group) confers a large dipole moment to the compound. The most similar compound would be the one that resembles ethanoic acid in these respects.Thus, I would say that the answer is (2) C2H5OH. Because oxygen is highly electronegative, it can retain an extra electron without much difficulty, making the hydroxyl group slightly acidic. The hydroxyl group also confers a large dipole moment, and the 2 carbon backbone indicates similar Van der Waals interactions.

What defines the mass number of an isotope? the sum of the neutrons and protons the sum of the neutrons and electrons the number of neutrons the number of protons

Answers

Answer:

The mass number of an isotope is the sum of neutrons and protons.

Explanation:

In any elemental isotope, the only things that will affect molar mass and mass number is the number of protons and neutrons. Electrons are not counted because we usually assume they are equal to the amount of protons and have no weight.

Protons are what gives the element its atomic number and the neutrons determine the type of isotope it is within the element.

For instance:

There can be a regular Carbon - 12

But there are isotopes like Carbon - 13 and Carbon - 14.

*The number of protons stays the same but the number of neutrons are different

List down the types of intermolecular forces that exist between molecules (or basic units) in the species given below: (a) benzene (C6H6), (b) CH3Cl, (c) PF3, (d) NaCl, (e) CS2

Answers

(a) benzene (C6H6) - nonpolar molecules . Only dispersion forces are present.

(b) CH3Cl -  Chloroform ; polar molecules. Both dispersion and dipole-dipole forces are present.

(c) PF3 -  Phosphorus triflouride ; has polar bonds but has nonpolar molecule due to its symmetrical structure. Only dispersion forces are present.

(d) NaCl - Sodium chloride ; ionic compound. Both ion-ion and dispersion forces are present.

(e) CS2 - Carbon disulfide ; nonpolar molecules. Only dispersion forces are present.
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How is electron movement related to covalent bonding in ammonia, NH3?A) Electrostatic sharing in a sea of electrons around the atoms allows bonds to form. B) The atomic orbitals overlap and electrons are shared between the atoms forming bonds. C) A transfer of electrons forms ions which are electrostatically attracted forming bonds. D) Orbital exchange occurs between the atoms to redistribute the electrons and form bonds.