Essential Ideas

Question: Calculate these masses 

a) What is the mass of 6.00 cm³ of mercury, density = 13.5939 g/cm³?

b) What is the mass of 25.0 mL octane, density = 0.702 g/cm³?

Question: Calculate these masses 

a) What is the mass of 4.00 cm³ of Sodium, density = 0.97 g/cm³?

b) What is the mass of 125 mL gaseous chlorine, density = 3.16 g/L?

Convert the boiling temperature of gold, \(2966{\rm{ }}^\circ C,\) into degrees Fahrenheit and kelvin.

Question: What is the ratio of the average kinetic energy of a \({\rm{S}}{{\rm{O}}_{\rm{2}}}\) molecule to that of an \({{\rm{O}}_{\rm{2}}}\) molecule in a mixture of two gases? What is the ratio of the root mean square speeds, \({{\rm{u}}_{{\rm{rms}}}}\), of the two gases?

Convert the temperature of dry ice, \( - 77{\rm{ }}^\circ C,\) into degrees Fahrenheit and kelvin.

Physiological saline concentration-that is, the sodium chloride concentration in our bodies-is approximately\(0.16{\rm{M}}\). A saline solution for contact lenses is prepared to match the physiological concentration. If you purchase \(25\;{\rm{mL}}\) of contact lens saline solution, how many grams of sodium chloride have you bought?

Calculate the \(pH\) at the following points in a titration of \(40\;mL(0.040\;L)\) \(of 0.100 M\)   barbituric acid (\({K_a} = 9.8\)\( \times 1{0^{ - 5}}\) ) with\(0.100MKOH\) .

(a) no \(KOH\) added

(b) \(20\;mL of KOH\) solution added

(c) \(39\;mL\) of \(KOH\) solution added

(d) \(40\;mL\) of \(KOH\) solution added

(e) \(41\;mL\) of \(KOH\)  solution added

Convert 50 °F to °C and K.

Convert 80.92 °C to K and °F.

Hydrogen gas, H₂, reacts explosively with gaseous chlorine, \({\bf{C}}{{\bf{l}}_{\bf{2}}}\), to form hydrogen chloride, HCl(g). What is the enthalpy change for the reaction of 1 mole of \({{\bf{H}}_{\bf{2}}}\)(g) with 1 mole of \({\bf{C}}{{\bf{l}}_{\bf{2}}}\)(g) if both the reactants and products are at standard state conditions? The standard enthalpy of formation of HCl(g) is −92.3 kJ/mol.

Only a small fraction of a weak acid ionizes in aqueous solution. What is the percent ionization of acetic acid in a 0.100-M solution of acetic acid, CH₃CO₂H? 

CH₃CO₂H(aq) + H₂O(l) ⇌ H₃O⁺(aq) + CH₃CO₂⁻(aq)            Ka = 1.8 × 10−5 

(Hint: Determine [CH₃CO₂⁻] at equilibrium.) Recall that the percent ionization is the fraction of acetic acid that is ionized × 100, or

 [CH₃CO₂⁻] / [CH₃CO₂H] _initial × 100.

We can determine the relative acid strengths of NH₄⁺ and HCN by comparing their ionization constants. The ionization constant of HCN is given in Appendix H as 4.9 × 10⁻¹⁰. The ionization constant of NH₄⁺ is not listed, but the ionization constant of its conjugate base, NH₃, is listed as 1.8 × 10⁻⁵. Determine the ionization constant of NH₄⁺, and decide which is the stronger acid, HCN or NH₄⁺.

_{A sample of compound X ( a clear , colourless,  combustible liquid with a noticeable odor) is analyzed and found to contain 14.13g carbon and 2.96g hydrogen. A sample of compound Y ( a clear , colourless , combustible liquid with noticeable odor ) is analyzed and found to contain 19.91g carbon and 3.34g hydrogen. Are these data an example of the law of definite proportions, the law of multiple proportions, or neither? What do these data tell about substance X and Y ?}

(a) To three decimal places, what is the volume of a cube  with an edge length of ? (b) If the cube in part (a) is copper and has a mass of  what is the density of copper to two decimal places

Remove all of the blocks from the water and add the green block to the tank of water, placing it approximately in the middle of the tank. Determine the density of the green block.

(a) Add 2.334 ml. and 0.31 ml.

(b) Subtract 55.8752 m from 56.533 m.

What is the density of a liquid with a mass of 31.1415 g and a volume of 30.13 cm³?

An irregularly shaped piece of a shiny yellowish material is weighed and then submerged in a graduated cylinder, with results as shown.

(a) Use these values to determine the density of this material.

(b) Do you have any reasonable guesses as to the identity of this material? Explain your reasoning.

What is the volume in liters of 1.000 oz, given that 1 L = 1.0567 qt and 1 qt = 32 oz (exactly)?

Explain how you could experimentally determine whether the outside temperature is higher or lower than 0 °C (32 °F) without using a thermometer.

Identify each of the following statements as being most similar to a hypothesis, a law, or a theory. Explain your reasoning. 

(a) Falling barometric pressure precedes the onset of bad weather. 

(b) All life on earth has evolved from a common, primitive organism through the process of natural selection. 

(c) My truck’s gas mileage has dropped significantly, probably because it’s due for a tune-up

Identify each of the following statements as being most similar to a hypothesis, a law, or a theory. Explain your reasoning. 

(a) The pressure of a sample of gas is directly proportional to the temperature of the gas. 

(b) Matter consists of tiny particles that can combine in specific ratios to form substances with specific properties. 

(c) At a higher temperature, solids (such as salt or sugar) will dissolve better in water.

Identify each of the underlined items as a part of either the macroscopic domain, the microscopic domain, or the symbolic domain of chemistry. For any in the symbolic domain, indicate whether they are symbols for a macroscopic or a microscopic feature. 

(a) The mass of a lead pipe is 14 lb. 

(b) The mass of a certain chlorine atom is 35 amu. 

(c) A bottle with a label that reads Al contains aluminum metal. 

(d) Al is the symbol for an aluminum atom.

Identify each of the underlined items as a part of either the macroscopic domain, the microscopic domain, or the symbolic domain of chemistry. For those in the symbolic domain, indicate whether they are symbols for a macroscopic or a microscopic feature. 

(a) A certain molecule contains one H atom and one Cl atom. 

(b) Copper wire has a density of about 8 g/cm³.

(c) The bottle contains 15 grams of Ni powder. 

(d) A sulfur molecule is composed of eight sulfur atoms.

According to one theory, the pressure of a gas increases as its volume decreases because the molecules in the gas have to move a shorter distance to hit the walls of the container. Does this theory follow a macroscopic or microscopic description of chemical behavior? Explain your answer.

The amount of heat required to melt 2 lbs of ice is twice the amount of heat required to melt 1 lb of ice. Is this observation a macroscopic or microscopic description of chemical behaviour? Explain your answer.

Why do we use an object's mass, rather than its weight, to indicate the amount of matter it contains?

What properties distinguish solids from liquids? Liquids from gases? Solids from gases?

How does a heterogeneous mixture differ from a homogeneous mixture? How are they similar?

How does a homogeneous mixture differ from a pure substance? How are they similar?

How does an element differ from a compound? How are they similar?

How do molecules of elements and molecules of compounds differ? In what ways are they similar?

How does an atom differ from a molecule? In what ways are they similar?

Many of the items you purchase are mixtures of pure compounds. Select three of these commercial products and prepare a list of the ingredients that are pure compounds.

Classify each of the following as an element, a compound, or a mixture:

1. Copper
2. Water
3. Nitrogen
4. Sulphur
5. Air
6. Sucrose
7. a substance composed of molecules each of which contains two iodine atoms
8. gasoline

Classify each of the following as an element, a compound, or a mixture:

1. Iron
2. Oxygen
3. Mercury oxide
4. Pancake syrup
5. Carbon dioxide
6. a substance composed of molecules each of which contains one hydrogen atom and one chlorine atom
7. baking soda.

A sulfur atom and a sulfur molecule are not identical. What is the difference?

How are the molecules in oxygen gas, the molecules in hydrogen gas, and water molecules similar? How do they differ?

We refer to astronauts in space as weightless, but not without mass. Why?

As we drive an automobile, we don't think about the chemicals consumed and produced. Prepare a list of the principal chemicals consumed and produced during the operation of an automobile.

When elemental iron corrodes it combines with oxygen in the air to ultimately form red brown iron(III) oxide which we call rust. 

(a) If a shiny iron nail with an initial mass of 23.2 g is weighed after being coated in a layer of rust, would you expect the mass to have increased, decreased, or remained the same? Explain.

 (b) If the mass of the iron nail increases to 24.1 g, what mass of oxygen combined with the iron?

As stated in the text, convincing examples that demonstrate the law of conservation of matter outside of the laboratory are few and far between. Indicate whether the mass would increase, decrease, or stay the same for the following scenarios where chemical reactions take place:

(a) Exactly one pound of bread dough is placed in a baking tin. The dough is cooked in an oven at 350 °F releasing a wonderful aroma of freshly baked bread during the cooking process. Is the mass of the baked loaf less than, greater than, or the same as the one pound of original dough? Explain.

 (b) When magnesium burns in air a white flaky ash of magnesium oxide is produced. Is the mass of magnesium oxide less than, greater than, or the same as the original piece of magnesium? Explain. 

(c) Antoine Lavoisier, the French scientist credited with first stating the law of conservation of matter, heated a mixture of tin and air in a sealed flask to produce tin oxide. Did the mass of the sealed flask and contents decrease, increase, or remain the same after the heating?

Yeast converts glucose to ethanol and carbon dioxide during anaerobic fermentation as depicted in the simple chemical equation here:

\({\rm{Glucose}} \to {\rm{Ethanol + Carbon Dioxide}}\)

(a) If \(200.0g\) of glucose is fully converted, what will be the total mass of ethanol and carbon dioxide produced?

 (b) If the fermentation is carried out in an open container, would you expect the mass of the container and contents after fermentation to be less than, greater than, or the same as the mass of the container and contents before fermentation? Explain.

(c) If \(99.7g\)of carbon dioxide is produced, what mass of ethanol is produced?

Classify the six underlined properties in the following paragraph as chemical or physical: 

Fluorine is a pale yellow gas that reacts with most substances. The free element melts at -200⁰C and boils at -188 °C. Finely divided metals burn in fluorine  with a bright flame. Nineteen grams of fluorine will react with 1.0 gram of hydrogen.

Classify each of the following changes as physical or chemical: 

(a) condensation of steam

(b) burning of gasoline

(c) souring of milk

(d) dissolving of sugar in water 

(e) melting of gold

Classify each of the following changes as physical or chemical: 

(a) coal burning 

(b) ice melting 

(c) mixing chocolate syrup with milk 

(d) explosion of a firecracker 

(e) magnetizing of a screwdriver

The volume of a sample of oxygen gas changed from 10 mL to 11 mL as the temperature changed. Is this a chemical or physical change?

A 2.0 liter volume of hydrogen gas combined with 1.0 liter of oxygen gas to produce 2.0 liters of water vapor. Does oxygen undergo a chemical or physical change?

Explain the difference between extensive properties and intensive properties.

Identify the following properties as either extensive or intensive

1. Volume
2. Temperature
3. Humidity
4. Heat
5. Boiling point