General Chemistry: Foundations, Measurement, and Chemical Laws

Comprehensive flashcards covering essential general chemistry topics including mathematical preliminaries, classification and properties of matter, SI units, significant figures, chemical symbols and formulas, laws of chemical combination, and atomic history.

What calculator policy applies to chemistry exams according to the introductory lecture notes?

Graphing calculators are banned, but scientific calculators (such as the web 2.0 calculator and Desmos scientific) are allowed.

In scientific notation represented as $n \times 10^b$, what are the constraints on the coefficient $n$ and exponent $b$?

The coefficient $n$ must have exactly one non-zero digit before the decimal point, and the exponent $b$ must be an integer.

What are the values of Avogadro's number and Planck's constant as written in scientific notation in the lecture slides?

Avogadro's number is $6.022 \times 10^{23}\,\text{mol}^{-1}$ and Planck's constant is $6.262 \times 10^{-34}\,\text{J}\cdot\text{s}$.

How is a negative exponent defined, as shown in the example $5^{-3}$?

A negative exponent represents repeated multiplication of the reciprocal of the base number, calculated as $\frac{1}{5 \times 5 \times 5} = 0.008$.

What rule must be followed for expressions with implicit parentheses in fractional form such as $\frac{a+b}{c+d}$?

The numerator $(a+b)$ and denominator $(c+d)$ must be evaluated completely before performing division, represented as $\frac{(a+b)}{(c+d)}$.

How do you solve for $x$ in the logarithmic equation $\log(x) = -4.76$?

Apply the inverse log (antilog) by placing both sides as exponents on $10$, giving $x = 10^{-4.76} = 1.7 \times 10^{-5}$.

What is the difference between independent and dependent variables when plotting data on a graph?

The controlled independent variable is plotted on the horizontal x-axis, while the responding dependent variable is plotted on the vertical y-axis.

What is the distinction between interpolation and extrapolation on a data graph?

Interpolation determines $(x,y)$ pairs that lie between measured data points, while extrapolation determines $(x,y)$ pairs beyond measured data points.

What core concept is illustrated by this graph comparing two sets of data?

It illustrates directly proportional relationships (straight line passing through the origin) versus inversely proportional relationships (hyperbolic curve).

What is the standard form and solution equation for the quadratic formula?

For the standard quadratic equation $a x^2 + b x + c = 0$, the quadratic formula is $x = \frac{-b \pm \sqrt{b^2 - 4 a c}}{2 a}$.

What is the fundamental difference between an element and a compound?

An element is the simplest form of matter with unique physical and chemical properties that cannot be broken down, whereas a compound is a chemical combination of elements with a definite composition and distinct properties.

What characterizes a heterogeneous mixture compared to a homogeneous mixture?

A heterogeneous mixture is not uniformly mixed so samples can have different compositions, whereas a homogeneous mixture (solution) has a uniform composition throughout.

How does this flowchart subclassify all matter?

Matter is divided into Pure Substances (subclassified into Elements and Compounds) and Mixtures (subclassified into Heterogeneous Mixtures and Homogeneous Mixtures/Solutions).

What distinguishes physical properties from chemical properties?

Physical properties describe or identify a substance without changing its chemical composition, while chemical properties describe the characteristic chemical reactions a substance undergoes.

What is the difference between extensive and intensive properties, and which type can identify a substance?

Extensive properties depend on sample size (e.g., mass, weight), while intensive properties are independent of sample size (e.g., density, color, melting point) and can identify a substance.

What distinguishes physical changes from chemical changes regarding chemical composition?

In a physical change, the chemical composition of a substance is not altered; in a chemical change, reactants rearrange their chemical composition to form new products with different properties.

What does the Law of Conservation of Energy state?

Energy cannot be created or destroyed, but it can be converted from one form to another.

What are the distinct roles of hypotheses, theories, and scientific laws in the scientific method?

Hypotheses are tentative initial explanations based on observation; theories are broader testable explanations predicting linked phenomena; scientific laws are empirical statements of an observation without explanation.

Why can a hypothesis become a theory, but a theory can never become a scientific law?

A hypothesis can become a theory through supporting evidence, but a theory cannot become a law because laws are simple observations of phenomena rather than testable explanations.

What are the seven SI base units and their corresponding physical quantities?

Length (meter, $\text{m}$), Mass (kilogram, $\text{kg}$), Time (second, $\text{s}$), Temperature (Kelvin, $\text{K}$), Amount of substance (mole, $\text{mol}$), Electric current (Ampere, $\text{A}$), and Luminous intensity (Candela, $\text{cd}$).

What is the difference between accuracy and precision in scientific measurements?

Accuracy refers to how close the average measurement is to the true value, while precision refers to how close a set of measured values are to one another.

What are the rules for determining significant digits in multiplication/division versus addition/subtraction?

In multiplication and division, the result is limited by the measurement with the fewest significant digits; in addition and subtraction, the result is rounded to the place value of the estimated digit farthest to the left.

What are exact numbers, and how do they affect the significant digits of a calculated result?

Exact numbers include definitions, counted items, and integers in formulas; they do not limit the number of significant digits in a calculated result.

What is the rule for reporting significant digits when evaluating a logarithm or an inverse logarithm?

For $\log(x)$, the number of digits after the decimal point equals the number of significant figures in $x$; for an inverse log ($10^x$), the number of significant figures equals the number of digits after the decimal point in $x$.

How is density defined, what is its equation, and why is it classified as an intensive property?

Density is defined as mass per unit volume ($d = \frac{m}{V}$); it is an intensive property because its value is independent of sample size.

What formulas are used to convert between Fahrenheit ($T_F$), Celsius ($T_C$), and Kelvin ($T_K$)?

$T_C = \frac{5}{9}(T_F - 32)$, $T_F = \frac{9}{5} T_C + 32$, and $T_K = T_C + 273.15$.

What are the rules for writing element chemical symbols and chemical formulas?

An element symbol consists of 1 or 2 letters with the first always uppercase and the second lowercase; chemical formulas list element symbols with subscripts indicating the relative number of each atom in a compound.

What are the Latin names that serve as the basis for the chemical symbols of Sodium, Potassium, Iron, Lead, Mercury, and Tungsten?

Sodium is Natrium ($\text{Na}$), Potassium is Kalium ($\text{K}$), Iron is Ferrum ($\text{Fe}$), Lead is Plumbum ($\text{Pb}$), Mercury is Hydrargyrum ($\text{Hg}$), and Tungsten is Wolfram ($\text{W}$).

What does the Law of Conservation of Mass state, and who discovered it?

It states that during chemical reactions, matter is neither created nor destroyed (mass present after equals mass present before); it was discovered by Lavoisier in 1785.

What concept does this experimental setup demonstrate?

It demonstrates the Law of Conservation of Mass, showing that the total mass ($937.4\,\text{g}$) remains identical before, during, and after phosphorus burns in a closed bell jar.

What is the Law of Definite Proportions?

It states that any given compound is composed of definite proportions by mass of its constituent elements, so all pure samples of a compound have the same percent composition.

What is the Law of Multiple Proportions?

It states that when two elements form two or more compounds, the masses of one element that combine with a fixed mass of the second element are in ratios of small, whole numbers.

What additional insight about atomic structure did J.J. Thomson's experiments reveal beyond Dalton's atomic model?

Thomson showed that upon addition of electrical energy, different substances release identical negatively charged cathode rays, proving atoms are composed of smaller subatomic particles.

According to the lecture notes, what is the charge and mass calculation for a single electron?

Charge = $-1.60 \times 10^{-19}\,\text{C}$, and mass = $\text{charge} \times \frac{\text{mass}}{\text{charge}} = \frac{(-1.60 \times 10^{-19}\,\text{C})(1\,\text{g})}{-1.76 \times 10^8\,\text{C}} = 9.10 \times 10^{-28}\,\text{g}$.

What experiment is depicted in this figure, and what fundamental quantity did it determine?

It depicts Millikan's Oil-Drop Experiment, which was used to determine the charge of a single electron.