1. Chemistry/Physical Setting
Mid-Year Review
Br. Jabreal

2. Matter What is matter? How can matter be classified?
Anything that has mass and takes up space
How can matter be classified?
As a pure substance or a mixture.
Pure substance: Either an element or a compound (fixed chemical combination of two or more elements)
Mixture: Either heterogeneous or homogeneous

4. Phases of matter What are the phases that a substance can be found in?
Solid
Liquid
Gas
If the temperature is above a substance’s boiling point, the substance is a __GAS__
If the temperature is below a substance’s melting point, the substance is a __SOLID__

5. Extra Credit
A sample composed only of atoms having the same atomic number is classified as
(1) A compound
(2) A solution
(3) An element
(4) An isomer

6. Which diagram represents one substance in the gas phase?

7. Separating Mixtures
How could we separate a mixture of sand and water? By filtration.
What is distillation? A technique used to separate components of a mixture based on differences in their boiling points
How are components of dyes separated in chromatography? Based on differences in molecular polarity.

8. Which two samples could consist of the same substance?
Mass (g)
Volume (mL) A 30 60 B 40 50 C 45 90 D
120
Samples A and C because they both have the same density of 0.5 g/mL.

9. Given the balanced equation, representing a reaction:
2Na(s) + Cl2(g)  2NaCl(s) + energy
If 50 grams of Na and 60 grams of Cl2 react, what is the total mass of NaCl produced?
110g.

10. Significant Figures
How many significant figures are in each of the following?
123 m (3)
40,506 mm (5)
m (4)
x 104 g (5)

11. Percent Error
In an experiment, a student found that the percent of oxygen in a sample was 42.3%. If the accepted value is 39.3%, what is the magnitude of the experimental error?
*Use percent error equation from Table T

12. Temperature Extra Credit:
Heat moves from the object at the _higher____ temperature to the object at the __lower____ temperature.

13. Temperature Conversions
Convert each of the following into kelvin:
0 Celsius
58 Celsius
Convert each of the following into celsius:
280 K
190 K
*Use temperature equation from Table T

14. Extra Credit
At which Celsius temperature does Lead change from a solid to a liquid?
(1) 874 oC
(2) 601 oC
(3) 328 oC
(4) 0 oC

15. Structure of the Atom
What are the three subatomic particles found in an atom?
Protons
Neutrons
Electrons
The mass of a proton is closest to the mass of a(n) _NEUTRON_______.

16. Structure of the atom
_Protons__ and __neutrons__ are found in the nucleus. __Electrons__ are found outside orbiting the nucleus, and have a negative charge.
Ex. Carbon Atom

17. What is atomic number?
The number of protons in an atom of an element.

18. What are isotopes?
Isotopes are different versions of the same element. They have the same atomic number (number of protons) but a different number of neutrons.

19. How many protons, neutrons, and electrons?
Cl-35

20. Extra Credit
What is the difference between mass number and atomic mass?

21. Calculating Atomic Mass
To calculate the atomic mass, multiply the relative abundance in decimal form by that isotopes atomic mass for each isotope.

22. Extra Credit
Calculate the atomic mass of Gallium.

23. Electron Configuration
Which of the following represents the electron configuration of calcium in the excited state?
2-8-8

24. Emission Spectra
In terms of electrons and energy, describe how the atomic emission spectra of an element is produced.
When an excited electron returns to the ground state, the excited electron releases its extra energy in the form of light. The amount of energy released corresponds to specific wavelengths of light.

25. Extra Credit
According to the wave-mechanical model of the atom, what is the most probable region where an electron can be found?
Nucleus
Orbital
Quanta
Spectra

26. Periodic Table Which element is most chemically similar to chlorine?
(2) F
(3) Fr
(4) S

27. In terms of electrons, why are elements in the same group of the Periodic Table chemically similar?
They have the same number of valence electrons.

28. Which two characteristics are associated with metals?
Low first ionization energy and low electronegativity
Low first ionization energy and high electronegativity
High first ionization energy and low electronegativity
High first ionization energy and high electronegativity

29. Extra Credit
Why is the radius of a sodium ion smaller than the radius of a neutral sodium atom?
Sodium and other metals form ions by losing their valence electrons. When an atom loses electrons, it becomes smaller due to less electrons being present. Furthermore, it has less occupied energy shells as a result.

30. What are valence electrons?
Valence electrons are the electrons in the highest occupied (outermost) energy level.

31. Ion formation
Write the formula for the ion formed by each of the following: Na O N Al Ca

32. Extra Credit
Which subatomic particle plays the most important role in determining the chemical properties of an atom?
Proton
Neutron
Electron
Nucleus

33. Metallic Bonding
Describe metallic bonding.

34. Covalent Bonding What is covalent bonding?
What is the difference between a polar covalent and a nonpolar covalent bond?
What determines if a covalent bond will be polar or nonpolar?

35. Extra Credit A molecule must be nonpolar if the molecule (1) Is linear
(2) is neutral
(3) Has ionic and covalent bonding
(4) Has a symmetrical charge distribution

36. Extra Credit Given the equation representing a reaction: H + H  H2
Which statement describes the energy change in this reaction?
(1) A bond is broken as energy is absorbed
(2) A bond is broken as energy is released
(3) A bond is formed as energy is absorbed
(4) A bond is formed as energy is released

37. Lewis Electron Dot Structures
Draw the electron dot structure for each of the following:
CF4
CO2
H2O

38. Extra Credit
What is the molar mass of ammonium phosphate?

39. Extra Credit
Explain, in terms of particles, why a solution NaCl(aq) can conduct an electric current.
The solution contains mobile ions which can conduct electric currents.

40. Percent Composition Find the percent composition of C6H12O6.
*Use the percent composition equation from Table T.

41. Empirical and Molecular Formulas
What is the empirical formula of C6H12O6?
A compound has an empirical formula of CH2 and has a molar mass of 98.0 g/mol. What is the molecular formula of this compound?

42. Mole calculations
If you have 220 grams of CO2, how many moles of CO2 is this?
If you have 5.2 moles of NH3, how many grams of NH3 is this?
*Use the mole calculations equation from Table T

43. Balancing Equations Balance the following Equation:
__ NH3(g) + __O2(g) __N2(g) + __H2O(g) + energy