Chemistry Chapter 2 Test Flashcards

Questions and Answers

What is a hypothesis?

An untestable claim

An explanation of phenomena

A testable statement (correct)

A broad generalization

Which of the following defines a model?

A physical object only

An untested theory

A data collection strategy

An explanation of how phenomena occur (correct)

What is a theory?

A broad generalization that explains a body of facts or phenomena.

What is a quantity?

Something that has magnitude, size, or amount. Signup and view all the answers

What does SI stand for?

Le système International d'Unités. Signup and view all the answers

What is weight?

A measure of the gravitational pull on matter. Signup and view all the answers

What are derived units?

Units formed by combinations of SI base units. Signup and view all the answers

What is volume?

Amount of space occupied by an object. Signup and view all the answers

What is density?

The ratio of mass to volume. Signup and view all the answers

What is a conversion factor?

A ratio derived from the equality between two different units. Signup and view all the answers

What is accuracy?

Refers to the closeness of measurements to the correct or accepted value. Signup and view all the answers

What is precision?

Refers to the closeness of a set of measurements of the same quantity. Signup and view all the answers

What is percent error?

Calculated by subtracting the experimental value from the accepted value, dividing by the accepted value, and multiplying by 100. Signup and view all the answers

What are significant figures?

Digits known with certainty plus one final digit that is somewhat uncertain or estimated. Signup and view all the answers

What is scientific notation?

Numbers are written in the form M x 10^h. Signup and view all the answers

What does 'directly proportional' mean?

Two quantities are if dividing one by the other gives a constant value. Signup and view all the answers

What does 'inversely proportional' mean?

Two quantities are if their product is constant. Signup and view all the answers

What is the scientific method?

A logical approach to solving problems by observing and collecting data. Signup and view all the answers

The base units in the metric system include _______.

meters, kilograms, seconds, kelvin, mol. Signup and view all the answers

How are derived units formed?

By multiplying or dividing standard units. Signup and view all the answers

What are examples of derived units?

Cm^3. Signup and view all the answers

How many base units are there in the metric system?

<ol start="7"> <li></li> </ol> Signup and view all the answers

What equation is used for density?

D = m/v. Signup and view all the answers

What are possible units for density?

g/mL or g/cm^3. Signup and view all the answers

What must all conversion factors equal?

<ol> <li></li> </ol> Signup and view all the answers

What does 'milli-' mean?

1/1000. Signup and view all the answers

What does 'centi-' mean?

1/100. Signup and view all the answers

What does 'kilo-' mean?

<ol start="1000"> <li></li> </ol> Signup and view all the answers

What is the difference between accuracy and precision?

Accuracy refers to closeness to accepted value; precision refers to consistency among measurements. Signup and view all the answers

What is the equation for percent error?

Percent error = (value accepted - value experimental) / value accepted x 100. Signup and view all the answers

What is the rule for adding and subtracting significant figures?

The answer must have the same number of digits to the right of the decimal point as the measurement with the fewest. Signup and view all the answers

What is the rule for multiplying or dividing significant figures?

The answer can have no more significant figures than the measurement with the fewest significant figures. Signup and view all the answers

What is the general form of scientific notation?

M x 10^h. Signup and view all the answers

When moving the decimal in scientific notation, if the regular number gets bigger, what happens to the exponent?

It becomes negative. Signup and view all the answers

What is the rule for adding or subtracting with scientific notation?

Exponents must match before doing the math. Signup and view all the answers

What is the rule for multiplying with scientific notation?

Multiply the regular numbers and add the exponents. Signup and view all the answers

What is the rule for dividing with scientific notation?

Divide the regular numbers and subtract the exponents. Signup and view all the answers

What is the final step of each scientific notation equation?

Make sure it's in scientific notation. Signup and view all the answers

What equation shows a directly proportional relationship?

Y = kx. Signup and view all the answers

What would the graph of a directly proportional relationship look like?

A straight line. Signup and view all the answers

What equation shows an indirectly (inversely) proportional relationship?

XY = k. Signup and view all the answers

What would the graph of an indirectly proportional relationship look like?

A hyperbola. Signup and view all the answers

Study Notes

Key Terms in Chemistry Measurements and Calculations

Hypothesis: A testable statement that can be investigated through experiments.
Model: Represents an explanation of phenomena and the relationships between data or events, beyond just a physical object.
Theory: A broad generalization that provides explanations for a collection of facts or observed phenomena.
Quantity: Refers to an attribute that has magnitude, size, or amount.
SI (Le Système International d'Unités): The international system of units used for scientific measurements.
Weight: The measure of the gravitational force exerted on matter.

Units and Measurements

Derived Units: Created from combinations of SI base units; examples include cubic centimeters (cm³).
Volume: The amount of three-dimensional space occupied by a substance.
Density (D): Defined as mass (m) divided by volume (v); common units include grams per milliliter (g/mL) or grams per cubic centimeter (g/cm³).

Measurement Accuracy and Precision

Accuracy: Refers to how close measurements are to the accepted value of the quantity.
Precision: Indicates the consistency and repeatability of a set of measurements.
Percent Error: Calculated as (\frac{\text{Accepted Value} - \text{Experimental Value}}{\text{Accepted Value}} \times 100).

Significant Figures and Scientific Notation

Significant Figures: Include all known digits plus one uncertain digit in a measurement.
Scientific Notation: Represents numbers in the form (M \times 10^h), where (M) is between 1 and 10, and (h) is an integer.
Rules for significant figures:
- Addition/Subtraction: The result should have the same number of decimal places as the measurement with the fewest decimal places.
- Multiplication/Division: The result must match the number of significant figures in the least precise measurement.

Conversion and Relationships

Conversion Factor: A derived ratio that allows for conversion between different units, equaling 1.
Directly Proportional: Two quantities where dividing one by the other yields a constant value; represented mathematically as (y = kx), resulting in a straight line on a graph.
Inversely Proportional: Two quantities whose product is constant; mathematically represented as (xy = k), producing a hyperbola graph.

Scientific Method Steps

Steps of the Scientific Method:
- Formulating a question.
- Gathering information.
- Stating a hypothesis.
- Conducting experiments.
- Recording and analyzing data.
- Drawing conclusions.

Base Units in the Metric System

Base Units: There are seven fundamental base units, including:
- Meters (length)
- Kilograms (mass)
- Seconds (time)
- Kelvin (temperature)
- Moles (amount of substance)

Miscellaneous

Derived Unit Formation: Created by multiplying or dividing standard units.
Prefix Definitions:
- Milli-: Represents a factor of (1/1000).
- Centi-: Represents a factor of (1/100).
- Kilo-: Represents a factor of (1000).
Final Scientific Notation Step: Ensure that the result is formatted correctly in scientific notation before concluding calculations.

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Description

Prepare for your Chemistry exam with these flashcards covering key concepts from Chapter 2. Learn essential terms like hypothesis, model, theory, and quantity to reinforce your understanding of measurements and calculations in chemistry.