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Chemistry Activity / Study Guide
Define the following ​in your own​ words:
Matter - A matter is a substance which has mass and occupies space by volume
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Element -An atom is substance whose all atoms have the same number of protons
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Proton - A proton is a subatomic particle with a positive charge equal to its number of electrons
Neutron -A neutron is a subatomic particle without any charge on it
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Mass number (=atomic weight) -Mass number is the total number of protons and neutrons in a nucleus
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Electron -An electron is a negatively charged subatomic particle
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Orbital -Orbitals are the imaginary lines which describes where an electron is likely to be found
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Half-life -Half life is a time taken for the radioactivity of a specified isotope to fall to half its original value
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Ion -An ion is an atom which has electric charge by gaining or losing energy
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Ionic bond -Ionic bond is a kind of chemical bond in which positively charged ion forms bond with negatively charged ion
by transferring of electrons
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Ionization - Ionization is the process in which electrically neutral atom gets charged by heat or radiations
Molecule -A molecule is the particle consisting of two or more atoms bonded together
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Acid - Acid is a substance that produces H+ ions and turns blue litmus red
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Hydrogen ion -hydrogen ion is negatively charged ion with one hydrogen ion found in all acid
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pH -pH is a measure of the hydrogen ion , a measure of acidity or alkalinity
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Non-polar covalent bond - It is a kind of bond which is formed when electrons are equally shared between two atoms
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Ionic bond -Ionic bond is the bond between two ions by transfer of electrons
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Cation -A positively charged ion
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Hydrophobic - A hydrophobic is the property of a molecule in which substance does not dissolve in water
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Hydrophilic -A hydrophilic is the property of a molecule in which substance easily mix up with water
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Capillarity (=capillary action) - It is the property of fluid to flow in narrow tubes
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Freezing point of water -​The temperature at which the liquid changes to solid state
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Solvent - A solvent is a component in a solution that is present in greater amount
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Aqueous solution -It is the solution in which water is the solvent
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Indicate what is meant by electrons in an "excited state" and those in a "ground state"
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Atomic structure of an atom is comprised of three subatomic particles : protons , neutrons and electrons
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orbiting around the nucleus are electrons
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The
atomic mass of an element is the total number of protons and neutrons present
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electrons have negative charge
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when an element receive energy by heat or any radiation , the electrons get excited and jumps to its higher energy level

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2
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Define half-life
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Ans : ​Isotope is an element having the same number of protons but different number of neutrons in nuclei
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That's because they have 
the same numbers of protons and electrons
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Half-life -Half life is a time taken for the radioactivity of a specified isotope to fall to half its original value ​
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Using clear and well labeled diagrams, explain what an ion is, and how it forms
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Ans - An ion is an atom or molecule having a net positive or negative charge
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Ionic bond is a kind of bond where complete transfer of valence electrons
take place between two oppositely charged ions​
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Generally 
when the electronegativity of two atoms are far away they form an ionic bond
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Explain what is meant by pH
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Use complete sentences for both
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Buffer solution resist a change in pH
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5
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Relate the structure of
an atom to its chemical properties and to the type of chemical bond it forms, using complete sentences and/or well
labeled diagrams
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Ionic bond involves the
complete transfer of valence electrons
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​whether the atom will lose, gain, or share electrons with other atoms to become stable​
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Atomic mass is determined by the total number of protons and neutrons
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Describe the special physical properties of water, using complete sentences
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Explain why water is a good solvent, using complete sentences
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Ans : physical properties of Water (H2O) are :
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capillary action
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polarity
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An individual water molecule is held by polar covalent bond
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so oxygen atom has a partial negative charge and hydrogen atom has a partial
positive charge
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which is known as hydrogen bonding
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Thus water is a universal solvent
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waters high surface
tension is due to hydrogen bonding in it
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How do the unique chemical and physical properties of water make life on earth possible? (Use complete sentences
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Ans : Human body consists 70% of water
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It
also helps in maintaining the pH level of the body
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water allows the body
to absorb and eliminate minerals , vitamins ,amino acid glucose and many other substances
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In plants , due to its cohesive property it helps in transpiration
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without enough water plant droops
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8
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Ans : ​Oxygen and carbon dioxide are basic to life because they are required for energy for all organisms on earth
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They are involved in the process of respiration and
photosynthesis
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How do compounds and molecules differ from each other? (Use complete sentences and an example of each
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A compound is a substance which is
formed by one or different kinds of elements which are combined together in a fixed proportion
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What is the difference between a polar and nonpolar covalent bond? (Use complete sentences and an example of
each
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Non polar covalent bonds​ are a type of bond that occurs when two atoms share a pair of electrons with each other
example of polar covalent bond - HF where hydrogen have partial negative charge and fluorine have partial positive
charge
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11
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(Use complete sentences and an
example of a buffer system
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Homeostasis is the ability of an organism to maintain internal balance
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​When any acidic
substance enters the bloodstream, the bicarbonate ions neutralize the hydronium ions forming carbonic acid
and water
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Thus hydronium ions are
removed, preventing the pH of blood from becoming acidic
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When a strong acid
is added, the base present in the buffer neutralizes the hydronium ions



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