HESI EXAM REVIEW - CHAPTER 6 CHEMISTRY

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HESI EXAM REVIEW - CHAPTER 6 CHEMISTRY

Actual Qs and Ans Expert-Verified Explanation

This Exam contains:

-Guarantee passing score -100 Questions and Answers -format set of multiple-choice -Expert-Verified Explanation Question 1: a _____ is the attraction for a hydrogen atom by a highly electronegative element.

• The elements generally involved are fluorine (F), oxygen (O), and nitrogen (N).
• Hydrogen bonds are about 5% to 10% as strong as covalent bonds, making them the

strongest of the intermolecular forces

Answer:

hydrogen bond Question 2: the speed of the electrons is so great that, in essence, they occupy the space around the nucleus as a cloud rather than as discrete individual locations. The electrons orbit the nucleus at various energy levels called ______ or _______

Answer:

shells or orbits Question 3: An ______ is an electrostatic attraction between two oppositely charged ions, or a cation and an anion

• This type of bond is generally formed between a metal and a nonmetal
• An excellent example of ionic bonding is salt ... since opposites attract, the positive cation will

attract the negative anion and form an electrostatic bond

• In this type of bond, the cation (sodium) takes one electron from the anion (chlorine) , which

makes the overall molecule electrically neutral

• This taking and giving of an electron completes the outer electron orbit, making both

substances very stable

• Sodium (Na+) needs one electron and Chlorine (Cl-) has an extra one
• Na+ + Cl ---> NaCl
• Sodium + chloride yields (table) salt

Answer:

ionic bond Question 4: _______ is a self-sustaining, exothermic (creates heat) chemical reaction where oxygen and a duel compound such as a hydrocarbon react

• in the combustion of hydrocarbon (gas or oil products), the products are carbon dioxide (CO2)

and water (H2O)

• The combustion of ethane (C2H6) would look like this in a chemical equation, where (g) stands

for gas

• 2C2H6 (g) + 7O2 (g) ---> 4CO2 (G) + 6H2O (g)

Answer:

combustion Question 5: an atom in an ionic state will have lost electrons, resulting in a net positive charge, or will have gained electrons resulting in a net negative charge

• The atom is called a ____ if it has a positive charge and an ____ if it has a negative charge

Answer:

cation, anion Question 6: Series of rules to determine what has been oxidized and what has been reduced..

Answer:

• The oxidation of any elemental atom is zero. This means that if an atom is in its natural state, its

charge or number is zero. Most elements in their standard states are single atoms. However, a few expectations exist including hydrogen (H2) , bromine (Br2) , oxygen (o2), nitrogen (N2), Iodine (I2) and fluorine (F2). When these elements exist outside of a compound in their natural state, they are always in pairs

• The oxidation number of any simple ion is the charge of the ion. if in a reaction, sodium (Na) was

listed as an ion (Na+), it would have an oxidation number of (+1). If chlorine (Cl) was listed as an ion (Cl-), it would have an oxidation number of minus one (-1)

• The oxidation number for oxygen in a compound is minus two (-2)

• The oxidation number for hydrogen in a compound is (+1)

• The sum of the oxidation numbers equals the charge on the molecules of polyatomic ions

Question 7: _____ is defined by its properties. it can also be stated that the property of matter comes from the properties of its composite elements and the periodic table organizes the elements based on their structure and thus helps predict the properties of each of the elements

Answer:

matter

Question 8: What are the three most common temperature systems

Answer:

Farenheit, Celsius, and Kelvin Question 9: _____ is often described as the opposite of synthesis because it is the breaking of a compound into its component parts

• NaCl ---> Na + Cl -
• When placed in an aqueous solution, table salt (NaCl) decomposes or breaks apart into an

ionic solution of sodium (Na+) as a cation and chloride (Cl-) as an anion

Answer:

decomposition

Question 10: Mixtures of matter that readily separate such as water and oil.

Answer:

emulsions

Question 11: When a reaction occurs, the product is generally a _____

• A molecule may have a subscript written after the chemical molecule as in O2, which is oxygen

Answer:

molecule Question 12: ______ also called alkaline compounds, are substances that denature proteins, making them feel very slick; they change red litmus paper blue and become less basic when mixed with acids

Answer:

bases Question 13: _______ is expressed as weight per weight, as in gram per grams, weight per volume, as in grams per liters; or volume per volume, as in milliliters per liter

Answer:

Concentration

Question 14: Group IA has a plus one (+1) charge, group IIA has a positive two (+2) charge, and group IIIA has a positive three (+3) charge Group IVA can have either a positive four (+4) or a negative four (-4) charge... The negative charges are as follows: group VA has a negative three (-3) charge, group VIA has a negative two (-2) charge, and group VIIA has a negative one (-1) charge

Answer:

The periodic table makes it possible to predict the charge of an atom or element, when it exists as an ion, by its location in the table

Question 15: It is not possible to have oxidation without reduction

• The element that is oxidized (loses electrons) is the reductant or reducing agent, and the

element that is reduced (gains electrons) is the oxidant or oxidizing agent

• Even though a substance is oxidized and gains an electron, its ionic charge is more negative;

likewise, a substance that is reduced loses an electron, and its ionic charge is more positive

Answer:

oxidation and reduction

Question 16: The _____ designates whether the number is positive or negative

Answer:

mathematical sign Question 17: There is an understood (+) before a positive significand and there is in all positive numbers

Answer:

HESI hint*** Question 18: When writing a number between -1 and +1 , always place a zero (0) to the left of the decimal. Write 0.62 and -0.39 (do not write .62 or -.39) to avoid mistakes when reading the number and locating the decimal

Answer:

HESI hint*** Question 19: Some comparisons may give more insight to sizes or amounts. A meter is a little more than 3 inches longer than a yard. A dime is a little less than 2 cm in diameter. A kilogram is about 2.2 lb. A liter is a little more than a quart

Answer:

HESI hint***