Midterm Review Test Questions – Flashcards
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Unlock answers| Burning of paper Physical or chemical change |
| Chemical |
| Dissolving of sucrose Physical or chemical; |
| physical |
Which substance is an organic molecule? H2O NaCl CuSO4 C2H5OH |
| C2H5OH |
What state of matter is bromine at 65oC? Melting Pt = -7oC Boiling Pt = 59oC |
| Gas |
What property of matter was the chromatography lab based on?
|
| Solubility |
| What type of mixture is salt water? |
| Homogeneous |
What type of mixture can be filtered? Homogeneous or heterogeneous |
| Heterogeneous |
| A substance that cannot be broken down by any physical or chemical means is ... |
| Element |
In the reaction; 2 H2 + O2 --> 2 H2O How much water would form if 18 grams of H2 react with 144 grams of O2? |
| 162 grams |
| What scientific law is used in the previous example? |
| Law of Conservation of Mass |
| The fact that sodium explodes in water is an example of what type of property? |
| Chemical |
| Distillation is a process that separates a mixture of liquids based on what property? |
| Boiling point |
Round off the numbers to 3 significant figures: 57.023
450.00896
5.78 x 105 |
57.0
40.0
5.78 x 10 |
How many significant digits are in each of the numbers? a)123.006
b)0.00120
c) 1.76 x 103 |
a) 6 [123.006]
b) 3 [0.00120]
c) 3 [1.76 x 103] |
What is the answer to the correct number of significant digits?
12.011 + 2.5 |
14.5 Because the 2.5 has only 1 decimal which determines the S.F. in an addition/subtraction problem |
What is the answer to the correct number of significant digits?
25.55 / 5.0 |
5.1 because the 5.0 has only 2 S.F. which is the determining factor when multiplying or dividing |
| Convert 14.2 cm to kilometers |
| .000142 |
| How many nanometers in 6 mm? |
| 6,000,000 |
A car travelling at 65 mph is travelling how many Km per min?
(1 mile = .6 Km) |
1.73 km/min
65mph x 1.6 km/mi x 1 hr/60 mins
|
| What part of Dalton's atomic theory has been amended? |
Atoms are now divisible.
AND
Atoms of the same element can have different atomic masses. |
| What subatomic particle is a cathode ray made of? |
| Electrons |
What particle did Rutherford aim at gold foil? What does the particle consist of? |
Alpha beam 2 protons and 2 neutrons (a Helium nucleus) |
| How many protons, neutrons and electrons are in the element P - 32? |
| 15 protons, 15 electrons, 17 neutrons |
| Write the symbol for an isotope of Si -14? |
| Si-15 or Si-16 |
| According to the band of stability, what particles are in a 1:1 ratio, then a 1:1.25 ratio for atomic stability? |
| 1 proton to 1 or 1.25 neutrons |
| What particle determines the identity of an element? |
| Number of protons |
| What particle determines the chemical reactivity of an element? |
| Electron |
| What are the sublevels in the 4th pricipal energy level? |
| s, p, d, f |
| What is the maximum number of electrons in the "d" sublevel? |
| 10 |
| What part of the Periodic Table has the "d" sublevel filling in? |
| Transition Metals |
| What is the electron configuration of Si? |
| 1s22s22p63s23p2 |
Identify the element:
1s2 2s2 2p6 3s2 3p6 4s2 3d1 |
| Scandium |
What must be true of electrons in the same orbital?
|
| They have opposite spins |
| What are the orbital orientation in the "p" sublevel? |
| px py pz |
| Why does hydrogen get placed with the alkali metals on the periodic table/ |
| Because it has 1s1 as its electron configuration |
| What atomic property explains why the noble gases are inert? |
The noble gases have a stable octet s2p6 |
| What is the trend for Ionization energy across a period? |
| Ionization energy increases across a period. |
| Explain the Ionization energy trend. |
| Going across a period the nuclear charge increases while the electron shielding stays the same so it is harder to remove the electron. |
which has the larger atomic radius Al or Cl? |
| Cl |
Which has the larger Ionization Energy
Na or Rb |
Na Because it has less electron shielding |
How many electron shields are present in an atom of Bromine? |
| 3 |
Name the compound Na3P |
| Sodium phosphide |
Write the formula for dinitrogen pentaoxide.
Is it an ionic compound? |
N2O5 No - because it is composed of 2 nonmetals. |
Name the compound
Mg CO3
What type of compound is it? |
magnesium carbonate
an ionic compound |
What type of element is this
It has a shiny luster, is malleable and conducts electricity |
metal |
This element has an incomplete "d" sublevel, Where is it on the periodic table? |
| Transition Metals |
This element has the outer energy level s2 p 6 What family is it? |
| Noble Gases |
| This element has 5 electrons in the outer 4th energy level? |
Arsenic |
| This is the only positive polyatomic ion |
| Ammonium NH4 |
Is this electron configuration "excited"
1s2 2s2 2p6 3s2 3p6 4s2 4p1 |
Yes - because the last electron should fill in 3d1 |
What is the frequency of a blue light with a wavelength of 450 nm?
|
3 x 108 m/sec = wl x (450 x 10-9)
6.66 x 1014 Hz |
| Which type of electromagnetic radiation has the shortest wavelength? |
| Gamma |
| What part of the electromagnetic spectrum has the highest frequency? |
| Gamma |
| What part of the electromagnetic spectrum do we use for cooking? |
| Microwaves |
What is amount of energy in light with a frequency of 4.5 x 1014 Hz? |
E = h Freq (Panck's constant)
(6.626 x 10-34 ) x (4.5 x 10 14)
2.98 x 10-19 joules |
| What is the difference between an extensive and intensive property? |
| Extensive properties deal with the amount of a substance while intensive properties are specific to the material. |
| Give example of an intensive property. |
Density Boiling point Melting Point
|
Tell the number of protons, neutrons, and electrons in the following;
Cl - 35 |
Cl - 35
Protons 17 Neutrons - 18 Electrons - 17 |
Tell the number of protons, neutrons, and electrons in the following:
28 +3 Al 13
|
Protons - 13 Neutrons - 15 Electrons - 10 |
Which is an example of an isotope for
35 Br - 80 |
34 Se - 80
80 Hg - 200
35 Br - 81 |
In the nuclear reaction;
U-238 --> Th 234 + ____
what is the other product? |
Alpha particle
4- He - 2 |
| which particle results in the product's atomic number increasing by 1? |
Beta
-1 e o |
