Molecular forensic science

1-3 chapters

An astronaut uses a laboratory balance and weighs an object on earth and again on the moon. Which statement below about the weight and mass of the object is true?

The mass will be the same on earth and moon but the weight will be less on the moon.

Most of the alpha particles directed at a thin gold foil in Rutherford's experiment

passed directly through the foil undeflected.

Which of the following represent isotopes?

A and C

Which are isotopes? An atom that has an atomic number of 34 and a mass number of 76 is an isotope of an atom that has

an atomic number of 34 and a mass number of 80.

Which of the following two atoms are isotopes?

¹²C₆ and ¹³C₆

passed directly through the foil undeflected.

an electron

The existence of neutrons in the nucleus of an atom was demonstrated by

None of the above

Which of the following is not explained by Dalton's atomic theory?

the existence of more than one isotope of an element

The current model of the atom in which essentially all of an atom's mass is contained in a very small nucleus, whereas most of an atom's volume is due to the space in which the atom's electrons move was established by

Rutherford's gold foil experiment

The charge-to-mass ratio of an electron was established by

Thomson's cathode ray tube experiment

The existence of electrons in atoms of all elements was demonstrated by

Thomson's cathode ray tube experiment

Elements A and Q form two compounds. The ratio (mass Q)/(mass A) for compound one is 0.271 and ratio (mass Q)/(mass A) for compound two is 0.362. If compound one has the chemical formula AQ, what is the chemical formula for compound two?

A3Q4

Elements A and Q form two compounds, AQ and A2Q. Which of the following must be true?

(mass Q)/(mass A) for AQ must be 2 times (mass Q)/(mass A) for A2Q

Elements A and Q form two compounds, AQ and A2Q3. The mass ratio (mass Q)/(mass A) for AQ is 0.574. What is the mass ratio (mass Q)/(mass A) for A2Q3?

0.861

Which of the following is a part of Dalton's atomic theory?

Atoms are rearranged but not changed during a chemical reaction.

Which of the following statements is not a postulate of Dalton's atomic theory

Atoms are composed of protons, neutrons, and electrons.

24.0 g of which element contains the greatest number of atoms?

B

One mole of which element has the smallest mass?

Ni

What is the standard isotope that is used to define the number of atoms in a mole?

12C

The observation that hydrogen and oxygen can react to form two compounds with different chemical and physical properties, one having an O:H mass ratio = 8:1 and the other having an O:H mass ratio = 16:1 is consistent with the law of

multiple proportions

Identify physical properties (more than one)

• Color

• Hardness

Convert 7,585 µL to mL

7.585 mL

Convert 6.9 inch to cm

17.53

How many significant figures are in each of the numbers below?

1

200

3

1.27×105

4

2005

2

0.0032

Convert 0.00350 to scientific notation.

3.50×10-3

Write the answer to the mathematical problems below with the correct number of significant figures.

(14.3 − 2.3) ÷ 2.00

6.00

A mass of mercury occupies 0.750 L. What volume would an equal mass of ethanol occupy? The density of mercury is 

 and the density of ethanol is 0.789 g/mL

12.9 L

Calculate the mass of an object given the density of 2.186 g/mL and volume of 24.22 mL. (Report your answer to 2 decimal places.)

52.94 g

Calculate the volume of an object given the density of 1.910 g/mL and mass of 17.08 g. (Report your answer to 2 decimal places.)

8.94 mL

Calculate the density of an object given the mass of 5.38 g and volume of 4.71 mL. (Report your answer to 2 decimal places.)

1.14 g/mL

Specific gravity of a liquid is often defined as the ratio of the density of a substance to the density of water. If the specific gravity of X relative to water is 0.800 and the specific gravity of Y relative to water is 1.50, which of the following statements is false?

If X is a liquid, Y will float on X.

Which set of numbers below represents measurements that have good precision and good accuracy? The true value of the measurement is 4.75

4.79, 4.68, 4.81, 4.83

Write the answer to the mathematical problems below with the correct number of significant figures.

3967 × 0.022 ÷ 9.09

9.6

Write the answer to the mathematical problems below with the correct number of significant figures.

1.45 + 101 − 11.92

91

Convert 3.3×10^-3 to decimal

0.0033

Convert 65 gal/day to L/s

0.0028 L/s

Convert 36 mi/hr to m/s

16

Convert 4,180 cm3 to dm3

4.18

Convert 2,116 mL to L

2.116

convert 0.420 g to mg.

420

Identify whether each of the following phrases relates to mass

• Measured in grams

• Independent of gravity

• Measures the amount of matter

Identify chemical properties (more than one).

• Inertness

• Explosiveness

Identify physical changes

• Formation of clouds and rain

• Freezing biological samples for storage

Identify the following as chemical changes (more than one)

• Toasting a marshmallow

• Burning documents

When measuring a solid metal block at constant temperature, which measurement will change in numerical value depending on the location where it is taken?

weight

What is the chemical symbol for tin?

Sn

Which group 1A element is not a metal?

H

Which of the following elements is a good conductor of heat and electricity?

zinc

All of the following elements are nonmetals except

antimony

transition metals

Which of the following statements does not describe a chemical property of oxygen?

The pressure is caused by collision of oxygen molecules with the sides of a container.

Which of the following statements does not describe a physical property of chlorine?

Chlorine combines with sodium to form table salt.

Which horizontal row of the periodic table contains the most elements?

row 6

Which of the following elements has chemical properties similar to oxygen?

Sulfur

Elements in a periodic group have similar

Chemical properties

Most elements in the periodic table are

Metals

Which is not true?

Mendeleev ended each row in his periodic table with an inert gas.

Which element has the chemical symbol, Au?

Gold

Mendeleev arranged the elements according to

atomic weight and chemical reactivity.

Which of the following elements is not a solid at room temperature?

Br

Which group of elements reacts violently with water?

alkali metals

Which of the following elements is a liquid at room temperature?

Mercury

Lithium belongs to the ___group of the periodic table.

alkali metal

The vertical columns of the periodic table are called

Groups

The horizontal rows of the periodic table are called

Periods

Calcium belongs to the What group

alkaline earth

Argon belongs to the what group

noble gas

Bromine belongs to

halogen

Chemically similar to E

B

Inner transition metal

Halageon

Alkaline earth metals

Noble gases

What is the chemical symbol for manganese?

Mn

Gases

Metals

Nonmetals

Alkali metals

Semi metals

Poor conductor of heat and electricity

Flourine

Gasses elements chaterogized by low reactivity in group

8A

5A element most metallic

Bi

Platinum chemical symbol

Pt

maganese chemical symbol

Mn

Element for symbols P

Phosphorus