Chemistry Midterm
FR1 How many calories did the metal lose?
-2.2 * 10^2 cal
An ion that ends in -ate has an acid name that ends with ___ and an ion that ends in ___ has an acid name that ends in -ous.
-ic. -ite.
FR2 What is the specific heat capacity of the metal?
0.024 cal/g degrees C
How many moles of phosphorus are in 4.00 g of phosphorus?
0.129 moles of phosphorus
What are some units of volume?
1 L = 1 dm^3 = 1000 cm^3 = 1000 mL
If d represents density, m represents mass, and V represents volume, which equation below is correct? A. d=V/m B. m=V/d C. V=d/m D. V=m/d E. all are correct
D. V=m/d
The coefficients in balanced chemical equations represent ___ ratios. A. particle B. mass C. mole D. a and c E. all of the above
D. a and c
Which dimensional analysis shown below correctly shows how units of mass and density can be combined to yield units of volume? A. cm*cm*cm=cm^3 B. g/mL * mL C. mL / g/mL D. g / g/mL
D. g / g/mL
Which of the following is an extensive property? A. boiling point B. melting point C. density D. mass E. electrical conductivity
D. mass
Which of the following describes a chemical property? A. water freezes at 0 degrees C B. water boils at 100 degrees C C. The density of water is 1.0 g/mL D. water decomposes into oxygen and hydrogen gases E. Table salt dissolves in water
D. water decomposes into oxygen and hydrogen gases
Which substance below is not an electrolyte? A. NaCl B. NaNO3 C. HCl D. NH4Cl E. C12H22O11
E. C12H22O11
Weight is inversely related to the square of the distance between an object and the center of the Earth. If the distance between an object and the center of the Earth is increased by a factor of three, the weight will ___ by a factor of ___. A. Increase, three B. Decrease, three C. Increase, four D. Decrease, six E. Decrease, nine
E. Decrease, nine
Which compound below is least soluble in water? A. NaCl B. NaNO3 C. NH4Cl D. KCl E. PbCl2
E. PbCl2
Which substance below contains metallic bonding? A. Carbon tetrachloride B. hydrochloric acid C. sodium chloride D. sulfur dioxide E. aluminum
E. aluminum
List the seven diatomic molecules using their diatomic symbols only.
H2, N2, O2, F2, Cl2, Br2, I2
A solution that turns red when universal indicator was added.
HCl because the universal indicator turns red when acidic and HCl is acidic because it contains hydrogen.
What are the formulas for hypochlorous acid and the perchloric acid?
HClO (aq) for hypochlorous and HClO4 (aq) for perchloric.
What is accuracy?
How close an observed measurement is to the accepted value.
What is precision?
How close an observed value is to the average value for the measurement.
The temperature on the surface of a planet is recorded to be -173 degrees C. What is the Kelvin temperature? A. 273 B. 173 C. 100 D. -100 E. -446
C. 100
How many grams of hydrogen are needed to form 36 g of water if excess oxygen is present? A. 1.0 B. 2.0 C. 4.0 D. 18 E. 36
C. 4.0
Which substance below is a nonelectrolyte? A. NaCl B. NaNO3 C. C6H12O6 D. NH4Cl E. AlCl3
C. C6H12O6
The volume of a sphere is directly related to the radius cubed. If the radius of a sphere is doubled, the volume will ____. A. increase by a factor of 2 B. increase by a factor of 4 C. Increase by a factor of 8 D. Decrease by a factor of 2 E. remain constant
C. Increase by a factor of 8
Which of the following is a polyatomic anion? A. O2 B. O^-2 C. O2^-2 D. NH4+1 E. NH3
C. O2^-2
Which equation below is incorrect? A. d = m / V B. m = d * V C. V = d / m D. V = m / d E. dV / m = 1
C. V = d / m
If a/ b-x = c / d, then d equals A. a / c(b-x) B. a / b-x - c C. c(b-x) / a D. ca / b-x E. (b-x) + c - a
C. c(b-x) / a
Which of the following is a derived quantity? A. mass B. length C. density D. time E. all of the above
C. density
Which of the following is an intensive property? A. mass B. volume C. density D. length E. weight
C. density
If a chemical change releases energy, it is ___ and the algebraic sign of q(heat) is ___. A. endothermic, positive B. endothermic, negative C. exothermic, negative D. exothermic, positive E. isothermal, negative
C. exothermic, negative
Which statement below is correct for describing solutions? A. Solutions are heterogeneous mixtures B. Solutions are pure substances C. Solutions have a definite composition D. Solutions can be separated by physical changes E. All statements are correct
D. Solutions can be separated by physical changes
What quantity is being measured if it is recorded in the following units? Cubic meters
Volume
What is the format for a combustion reaction?
hydrocarbon + O2 ---H2O + CO2
What is one of the most important equations that we will use all year and what do its symbols represent?
q=mc^T q= heat m = mass c = specific heat capacity ^T = change in temperature
The change in the temperature of the water has what kind of relationship with the amount of heat transferred?
A direct relationship.
What do chemists count in?
Moles
Steps of mass stoichiometry probelm
1. Convert the grams of the given substance to moles 2. Write the mole ratio between the known substance and unknown substance using the coefficients in the balanced chemical equation. 3. Convert the moles of unknown substance to grams of unknown substance.
What are the 5 main elements that have more than one charge?
1. Iron (Fe +2 or +3) 2. Copper (Cu + 1 or +2) 3. Gold (Au + 1 or + 3) 4. Tin (Sn + 2 or +4) 5. Lead (Pb +2 or +4)
What are the standard units in the metric system?
1. Mass = Kilogram 2. Length = meter 3. Time = seconds
FR1 What is the specific heat capacity of the metal?
2.0 * 10^2 cal/g degree C
FR1 How many calories did the water gain?
2.2 * 10^2 cal
Calculate the density of the piece of the 150.00 g metal using the volume calculated from the dimensions 5.75 cm, 3.50 cm, and 2.80 cm.
2.66 g/cm^3
What is the percent by mass of carbon in carbon dioxide?
27.3%
What is the equation of a thermochemical equation?
2H2 (g) + O2 (g) --- 2H2O (l) + HEAT
Calculate the density of the piece of the 150.00g piece of metal based on the volume determined by water displacement of 97 mL when the metal was added in the volume of water and 55 mL when it was just the volume of water.
3.6 g/mL
What are the prefixes for 4, 7, 9, and 10?
4 -tetra 7 -hepta 9 -nona 10 -deca
What is the format for a single replacement reaction?
A + BC --- AC + B
What does a pure substance have?
A fixed composition (formula) and distinct physical and chemical properties.
Define phase
A region of matter with a uniform set of properties.
How do you calculate accuracy and precision?
Accuracy: %E= (O-A) / A * 100 Precision: d= O - M (mean)
A solution that formed precipitates when mixed with HCl and NaCl.
AgNO3 because it formed the precipitate AgCl when mixed with B and D.
What is the difference between an empirical formula and a molecular formula?
An empirical formula shows the simplest ratios of atoms while the molecular shows the actual ratios of atoms, which may not show the simplest ratio.
What kind of relationship does the mass of water and the change of temperature have?
An inverse relationship.
What are some units of derived measurement?
Area (length*width), Volume (length*width*thickness), and density (mass / volume).
The compound CO2 is composed of ___ and the compound KF is composed of ___. A. molecules; atoms B. molecules; ions C. ions; molecules D. ions; atoms E. atoms; molecules
B. molecules; ions
What is the name of the acid with the formula HNO2? A. hydronitric acid B. nitrous acid C. nitric acid D. hyponitrous acid E. pernitric acid
B. nitrous acid
Two students wish to determine the specific heat capacity of copper. Each student heats a sample of copper metal and drops the heated metal into a calorimeter filled with 100 mL of water at room temperature. Student A uses twice the mass of copper as Student B. The change in temperature of the water for Student A will be ___ the change in temperature of the water for Student B and the calculated value for the specific heat capacity of copper for Student A will be ___ the calculated vale for the specific heat capacity of copper for Student B. A. greater than, greater than B. greater than, less than C. greater than, equal to D. less than, greater than E. less than, equal to
C. greater than, equal to
The change in temperature of a substance is ___ related to the ___. A. Inversely, amount of heat. B. directly, mass of substance C. inversely, specific heat capacity of the substance D. all of the above are true E. none of the above are true.
C. inversely, specific heat capacity of the substance
Which statement below is incorrect for describing solutions? A. solutions are mixtures B. solutions are homogeneous C. solutions have a definite composition D. solutions can be separated by physical changes E. all statements are correct
C. solutions have a definite composition
Which of the following is homogeneous? A. concrete B. apple C. water D. milk E. wood
C. water
A solution that is not electrically conductive.
C6H12O6 because it is not electrically conductive due to the fact that it is not ionic or metallic.
What is ductility?
Can be drawn into a wire.
What is malleability?
Can be pounded into thin sheets
Define mixture
Combinations of two or more substances in which each substance retains its own chemical identity.
What can be broken down chemically into elements?
Compounds
Which set of factors below convert nanoseconds to megaseconds? A. 1s / 10^-9 ns * 1Ms / 10^6 s B. 10^-9s / 1ns * 10^6Ms / 1s C. 10^6s / 1MS * 1ns / 10^-9s D. 10^-9s / 1ns * 1Ms / 10^6 s E. 10^6 Ms / 10^-9ns
D. 10^-9s / 1ns * 1Ms / 10^6 s
The missing coefficient needed to balance the equation below is ___. C3H8 + ?O2 --- 3CO2 + 4H2O A. 2 B. 3 C. 4 D. 5 E. 10
D. 5
Which compound below is least soluble in water? A. NaCl B. NaNO3 C. NH4Cl D. AgCl E. HCl
D. AgCl
The weight of an object is inversely related to the square of the distance from the center of the earth. If the distance between an object and the center of the earth is doubled, the weight will ___. A. increase by a factor of 2 B. increase by a factor of 4 C. decrease by a factor of 2 D. Decrease by a factor of 4 E. remain constant
D. Decrease by a factor of 4
What did Avogadro hypothesize?
Equal volumes of gases at the same temperature and pressure contain the same number of particles.
___ properties depend on the amount of material present.
Extensive.
What is a conversion factor?
Fractions which have a value of unity, that id, the numerator and denominator are equal.
What type of element and particles do ionic, covalent, and metallic bonds have?
Ionic - Metals (cations) and nonmetals (anions) - ion Covalent - nonmetal - molecules Metallic - metals - atom
Name the following compound: FeO
Iron (II) Oxide
How can the molecular formula be determined?
It can be determined from the empirical formula and the molecular mass of the compound.
What is Avogadro's number?
It is the number of atoms in a mole of any element. 1 mole= 6.023 * 10^23 atoms
What is the SI unit of temperature?
Kelvin
Name the following compound: PbO
Lead (II) Oxide
Review Picture 17 for Unit Test 2. Which line or curve below indicates that y is inversely related to x?
Line B
Free Response 2
Mass of metal 150.0 g Initial temperature of metal 100.0 degrees C Mass of water in calorimeter 50.0 g Initial temperature of water in calorimeter 25.0 degrees C Final temperature of mixture 30.0 degrees C Specific heat capacity of water 1.00 cal/g degrees C
Free Response 1
Mass of metal 160.0 g Initial temperature of metal 100.0 degrees C Mass of water in calorimeter 56.0 g Initial temperature of water in calorimeter 28.0 degrees C Final temperature of mixture 32.0 degrees C Specific heat capacity of water 1.00 cal/g degrees C
What are three units of basic measurement?
Mass, length, and time.
Magnesium metal reacts with chlorine gas. Write the balanced chemical equation. Include state symbols for reactants.
Mg (s) + Cl2 (g) --- MgCl2
A solution that gave a bright yellow flame test.
NaCl because sodium produced a yellow flame in the flame test.
Solutions of lead (II) nitrate and sodium chromate are mixed. Write a balanced equation for the double replacement reaction that occurs. Include physical state symbols for all substances.
Pb(NO3)2 (aq) + Na2CrO4 (aq) ---- PbCrO4 (s) + 2NaNO3 (aq)
What is an extensive property and what are some examples?
Properties that depend upon the amount of substance. Mass and volume.
What is an intensive property and what are some examples?
Properties that do not depend upon the amount of substance. Density and chemical properties.
What metals create what flames?
Sodium - Orange Lithium - Red Potassium - Pink Calcium - Orange Copper (II) - Green Strontium - Red Barium - Yellow
What happens when you pull away a positive particle from a negative particle?
The electrical potential energy of the particles increases.
What has the simplest atomic and mole ratio?
The empirical formula.
What is the molarity (M) of a solution?
The ratio of the moles of solute to the liters of solution.
What is water in an aqueous solution?
The solvent.
During the experiment Shanaynay accidentally drops the metal before getting it into the calorimeter containing the cold water. What effect will this error have on the calculated value?
The specific heat, in the end, would be higher because of the smaller change in heat. Since metals change in temperature quickly and the metal was dropped on the floor, the temperature will go down. Water, already with a lower change in temperature, will have the metal added to it, which was cooler than it initially was. Since this is an inverse relationship, the specific heat capacity will go up.
What is stoichiometry?
The study of the quantitative relationships between the substances involved in a chemical reaction.
What volume is one mole of gas at STP?
The volume is 22.4 L.
What is an endothermic change?
When heat flows from the surroundings into the system.
What kind of energy can be involved in a process?
Work, stored energy, or heat.
What is the symbol and meaning for: a. Giga b. Mega c. Micro D. nano
a. G 10^9 b. M 10^6 c. u 10^-6 d. n 10^-9
The pressure (P) a gas exerts is inversely related to the volume (V). Write a proportion to support this direct relationship.
t/d = K
What is the proportion for an inverse relationship?
xy = constant = k *Note: but you do dive to get inverse relationship answer. Curvy line.
What is the proportion for a direct relationship?
y/x = constant = k *Note: but you do multiply to get direct relationship answers. Straight line.
