Science study guide
Pure water has a pH of 7. Pure water___
Is neutral
Why is helium placed in group 18 on the periodic table?
It has a full outer shell
Lithium nitrate is a purple ionic solid. What is the chemical formula for lithium nitride?
Li N 3
The_______elements tend to lose electrons and form positive ions, while the _____elements tend to gain electrons and form negative ions.
Metal,nonmetal
Where are most metals and non metals located relative to the "stairstep" formed by metalloids?
Metals are found left of metalloids, nonmetals are found right of metalliods
Magnesium sulfide is an ionic compound that is often formed in the steelmaking process. What is the chemical formula for magnesium sulfide?
MgS
A homogeneous mixture in which one substance is dissolved in another substance is known a a(n)___
Solution
What is the name of the compound with the formula SO?
Sulfur Monoxide
Why should spray cans filled with gases be kept away from high heat of flames?
The gases over heat & atoms start to move/expand faster then it combusts
Which isotope contains the greatest number of protons?
They al contain same amount of protons
When does covalent bonding occur?
When pairs of electrons are shared by atoms.
Based on the models, was mass conserved in this chemical reaction? Explain.
Yes, all of the mass was balanced
When the solvent particles collide with the surface of the solute more often, the solute dissolves faster. Which of these will cause the solvent to collide with the solute more often? A.cooling the mixture B.using larger solute pieces C.stirring the mixture D.all of these
C.stirring the mixture
calcium nitride is an ionic compound that is formed when calcium burns in air. What is the chemical formula of calcium nitride?
Ca N 3 2
What are some common physical properties of ionic compounds?
High melting points High boiling points, conducts electricity
What is the solubility of potassium iodide at 30 C?
180g/cm3
If an element has a mass number of 4 and an atomic number of 2, how many neutrons does the element have?
2
How many valence electrons does a neutral atom of oxygen have?
6
A solution of baking soda has a pH of 9. Baking soda___
A base
Which statement describes and ionic bond? A. Electrons are transferred from one atom to another. B. Electrons are mobile within a metal. C. Electrons transition from an inner shell to a valence shel. D. Electrons are shared between atoms.
A. Electrons are transferred from one atom to another
Which of the compound is most likely to conduct electricity when dissolved in water? A. NaCl B. PCl5 C. CO2 D. CH4
A. NaCl
The acidity and basicity of a solution can be decreased by its pH. What type of ions are produced when acids are formed? How does the pH change as the ion concentration increases?
Acids form hydroxide ions as the ion concentration increases pH decreases.
A particular element has the following set of properties: • It has a low melting point. • It has a low boiling point. • It exists as a two-atom molecule in the gas phase. • It has seven outer electrons. • It readily reacts with metals to produce a salt. A.Hydrogen (H) B. Iodine (I) C. Xenon (Xe) D. Barium (Ba)
B. Iodine (I)
The acidity of a substance is measured using the pH scale. This scale ranges from 0 to 14. Which of the following substances has a pH of 7? A. Baking soda B. Pure water C. Orange juice D. Milk
B. Pure water
Which of the following explains how ions conduct electricity in a solution? A.The ions separate and become electrically neutral which allows the flow of current. B.The charged ions carry the current through the solution. C.The ions form a flexible solid that allows the transfer of a current. D.The ions form covalent bonds with water molecules, and current travels through the bonds.
B.The charged ions carry the current through the solution.
Which of the following elements is likely to form an ionic bond with potassium? A)calcium (Ca) B)lithium (Li) C)chlorine (Cl) D)gold (Au)
C) chlorine (Cl)
Which of the following features is common to both acids and bases? A.taste on the tongue B.pH level C.reaction with metals D.ability to burn skin
D.ability to burn skin
What is the name of the compound with the formula N O? 2
Dinitrogen monoxide
According to the law of conservation of mass, the mass of the reactants in a reaction must___ the mass of the products in a reaction.
Equal
Isotopes are atoms of the same element that have a different number of____
Neutrons
What is the name of the following compound: KCl?
Potassium chloride
What happens when the pressure on a gas such as the balloon is increased?
Pressure on balloon in increased,the volume will decrease
The atomic number of an element is determined by its number of___
Protons
If iodine has a atomic number of 53, how many protons and neutrons are found in the iodine- 129 atom?
Protons-53, neutrons- 76
What is the correct chemical formula for silicon dioxide?
S d, SLO 2
Sodium bromide is an ionic compound is an ionic compound that is sometimes used as a disinfectant for swimming pools. What is the chemical formula for sodium bromide?
Sb NaBr
