Matter Classification and Changes
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Questions and Answers

What is the chemical formula for the compound formed from Fe3+ and the oxide ion?

  • Fe2O3 (correct)
  • FeO3
  • Fe3O2
  • Fe3O

What is the correct name for the compound TiO2?

  • titanium oxide
  • titanium(II) oxide
  • titanium(IV) oxide (correct)
  • titanium dioxide

What is the name of the compound P4O10?

  • phosphorus(IV) oxide
  • tetraphosphorus decoxide (correct)
  • diphosphorus pentoxide
  • phosphorus oxide

How many atoms are present in 50 moles of sulfur?

<p>3.0E25 (D)</p> Signup and view all the answers

Determine the mass in grams of 2.70 × 10^23 atoms of potassium.

<p>17.5 (A)</p> Signup and view all the answers

Which statement must be true regarding the substances in the flask?

<p>A is an element. (A), B is a compound. (D)</p> Signup and view all the answers

What type of mixture involves two or more substances in variable proportions with constant composition throughout?

<p>A homogeneous mixture. (C)</p> Signup and view all the answers

Which of the following describes a chemical change?

<p>When heated, HgO forms elemental Hg and O2. (D)</p> Signup and view all the answers

Which order of quantities is correct from smallest to largest: 0.02 ng, 2 μg, 2 × 10^4 pg?

<p>0.02 ng &lt; 2 × 10^4 pg &lt; 2 μg (B)</p> Signup and view all the answers

What is the most probable identity of a metal with a volume of 118 cm³ and a mass of 929 g?

<p>Iron (D)</p> Signup and view all the answers

How many significant zeroes are in the number 0.030700?

<p>Three (A)</p> Signup and view all the answers

What is the correct answer when calculating 50.02 cm – 4.444 cm + 2.5 cm with proper precision?

<p>48.1 cm (A)</p> Signup and view all the answers

Which of the following best describes the scientific notation for (3.0 × 10^3)²?

<p>9.0 × 10^6 (C)</p> Signup and view all the answers

What is the result of the calculation $6.78 \times 5.903 \times (5.489 - 5.01)$?

<p>19 (C)</p> Signup and view all the answers

What describes the measurements of the copper pellets given their true mass is 10.5 g?

<p>Precise but not accurate (B)</p> Signup and view all the answers

How many cubic yards of concrete are needed to create a patio of dimensions 12 ft by 12 ft by 0.50 ft?

<p>2.6 (A)</p> Signup and view all the answers

If the walls of a room are 102 square meters and a gallon of paint covers 23.0 square yards, how many gallons are needed?

<p>5.30 gallons (D)</p> Signup and view all the answers

Which hypothesis in Dalton's atomic theory was proven incorrect by later experiments?

<p>Atoms of a specific element have the same mass. (D)</p> Signup and view all the answers

What key observation in the cathode ray experiments indicated that electrons have a negative charge?

<p>The cathode rays are deflected by a negatively charged plate. (C)</p> Signup and view all the answers

In Rutherford’s gold foil experiment, what conclusion was drawn about the nucleus?

<p>It is a very small dense core of the atom. (D)</p> Signup and view all the answers

How many protons, neutrons, and electrons are in a neutral atom of the isotope $^{13}C$?

<p>p+ = 6, n = 7, e– = 6 (D)</p> Signup and view all the answers

What is the calculated atomic mass of element 'Ma' based on provided isotopes?

<p>40.2 (C)</p> Signup and view all the answers

What is the charge on an atom containing 18 protons, 19 neutrons, and 20 electrons?

<p>2– (C)</p> Signup and view all the answers

Which of the following combinations indicates a molecular compound?

<p>Carbon dioxide (CO2) (D)</p> Signup and view all the answers

What is the most likely charge for tellurium (Te) as derived from the periodic table?

<p>2– (A)</p> Signup and view all the answers

What element has atomic number 16?

<p>Sulfur (C)</p> Signup and view all the answers

Which type of element is represented by the symbol Cl2?

<p>Molecular element (A)</p> Signup and view all the answers

Which statement about neutrons is correct?

<p>They have no charge. (D)</p> Signup and view all the answers

Flashcards

What is a compound?

A substance cannot be broken down into simpler substances by physical means, but can be broken down into simpler substances by chemical means.

What is a mixture?

A mixture contains two or more substances that are not chemically bonded and can be separated by physical means.

What is a homogeneous mixture?

A homogeneous mixture has a uniform composition throughout. Every part of the mixture has the same properties.

What is a heterogeneous mixture?

A heterogeneous mixture has a non-uniform composition. Different parts of the mixture have different properties.

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What is a chemical change?

A chemical change results in the formation of new substances with different properties.

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What is a physical change?

A physical change alters the form or appearance of a substance but doesn't change its chemical composition.

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How do you calculate density?

Density is a measure of how much mass is contained in a given volume. It's calculated as mass divided by volume.

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What are significant figures?

Significant figures are the digits in a number that are considered reliable and contribute to the precision of a measurement.

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Precise, but not accurate

Measurements are very close to each other, but the measurement is very far from the true value.

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Precise and accurate

Measurements are very close to each other, and to the true value.

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Neither precise nor accurate

Measurements are far from each other and far from the true value.

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Precision

A numerical representation of how closely repeated measurements of the same quantity agree.

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Accuracy

A numerical representation of how close a measurement is to the true value.

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Dimensional Analysis

A technique used to convert units within a single step.

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Dalton's atomic theory.

A statement that matter is made of very small, indivisible particles called atoms.

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Dalton's Atomic Theory – Hypothesis 1

Atoms of different elements have different masses.

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Dalton's Atomic Theory – Hypothesis 2 (incorrect)

Atoms of the same element have the same mass.

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Dalton's Atomic Theory – Hypothesis 3

Atoms of different elements can combine with each other in small, whole-number ratios to form different compounds.

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Dalton's Atomic Theory – Hypothesis 4

When atoms combine to form compounds, they do so in small, whole-number ratios.

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Atomic number

The number of protons in the nucleus of an atom.

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Mass number

The total number of protons and neutrons in the nucleus of an atom.

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Isotopes

Atoms of the same element with the same number of protons, but a different number of neutrons.

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Nucleus

The positively charged core of an atom, containing protons and neutrons.

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Iron(III) Oxide Formula

The chemical formula for an ionic compound formed from Fe3+ and the oxide ion (O2-) is Fe2O3.

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Name of TiO2

Titanium(IV) oxide (TiO2) is named using the Roman numeral to indicate the charge of the titanium ion.

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Name of P4O10

The name of P4O10 is tetraphosphorus decoxide. The prefixes indicate the number of atoms of each element.

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Empirical Formula

The empirical formula of carbon dioxide (CO2) and dicarbon tetroxide (C2O4) is the same: CO2.

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Mole to Atom Conversion

To convert between moles and atoms of an element, you use Avogadro's number (6.022 × 1023 atoms/mol).

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Study Notes

Matter Classification and Separation

  • Substance: A pure form of matter with a fixed composition.
  • Element: A substance that cannot be broken down into simpler substances by chemical means (e.g., gold, oxygen).
  • Compound: A substance composed of two or more elements chemically combined in a fixed ratio (e.g., water, carbon dioxide).
  • Mixture: Two or more substances physically combined in variable proportions; homogeneous mixtures have uniform composition throughout, while heterogeneous mixtures do not.

Chemical vs. Physical Changes

  • Chemical change: A change in which one or more substances are transformed into new substances with different properties (e.g., burning wood, rusting iron).
  • Physical change: A change that alters the form or appearance of a substance but does not change its chemical composition (e.g., melting ice, dissolving sugar).

Significant Figures and Calculations

  • Significant figures: Digits in a measured value that are known with certainty plus one uncertain digit. Follow rules for addition/subtraction and multiplication/division when rounding results to the correct number of significant figures.
  • Precision: How close repeated measurements are to each other.
  • Accuracy: How close a measurement is to the true value.

Density Calculations

  • Density: Mass per unit volume (g/cm³ or g/mL); used to identify substances.

Scientific Notation

  • Numbers in scientific notation are written as a coefficient multiplied by 10 raised to a power. Follow rules for calculations with scientific notation.

Metric Conversions and Dimensional Analysis

  • Use dimensional analysis to convert between units, ensuring units cancel appropriately. Conversion factors are used to make conversions from one unit to another.

Atomic Structure and Isotopes

  • Atomic number: The number of protons in an atom's nucleus. It defines the element.
  • Isotopes: Atoms of the same element with different numbers of neutrons, hence different mass numbers.
  • Atomic mass: The weighted average mass of all the naturally occurring isotopes of an element.
  • Protons, neutrons, and electrons: Protons and neutrons are in the atom's nucleus; the number of electrons in a neutral atom equals the number of protons. Isotopic symbols display mass number/atomic number and element symbol.

Ions and Chemical Formulas

  • Ions: Charged atoms (cations are positive, anions are negative).
  • Chemical formulas: Represent the composition of compounds showing the ratio of elements.
  • Naming chemical compounds: Use systematic rules for naming both ionic and molecular compounds
  • Empirical vs Molecular formulas: Empirical formulas give the simplest whole-number ratio of elements in a compound, while molecular formulas show the actual number of each type of atom in a molecule.

Moles and Atoms

  • Mole (mol): A unit representing 6.02 × 10²³ particles (atoms, molecules, or ions).
  • Molar mass: The mass in grams of one mole of a substance.
  • Use dimensional analysis to convert between moles and atoms or grams and moles.

Classifying Elements

  • Elements can be classified as atomic (monatomic elements; e.g. Argon) or molecular (diatomic elements; e.g. Chlorine)

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Description

This quiz explores the classification of matter, including substances, elements, compounds, and mixtures. It also covers the differences between chemical and physical changes along with the concept of significant figures in calculations. Test your understanding of these fundamental concepts in chemistry.

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