Some Basic Concepts of Chemistry

These flashcards cover key vocabulary and concepts related to basic chemistry principles as discussed in the lecture notes.

What is Chemistry?

a) The study of living organisms

b) The branch of science that studies the preparation, properties, structure, and reactions of material substances

c) The process of cell division

d) The study of stars and galaxies

Answer: b

What are the States of Matter?

a) Solid, liquid, gas

b) Solid, liquid, plasma

c) Gas, plasma, energy

d) Solid, liquid, energy

Answer: a

What is a Mole?

a) A unit of force

b) A unit representing 6.02214076 × 10^23 elementary entities

c) A measure of pressure

d) A unit of temperature

Answer: b

What is Atomic Mass?

a) The mass of an atom relative to hydrogen

b) The mass of an atom expressed relative to the carbon-12 isotope

c) The total mass of a molecule

d) The mass of an electron

Answer: b

What are SI Units?

a) A system for financial measurements

b) A standardized system for scientific measurements

c) A system used only in astronomy

d) A collection of metric units only

Answer: b

What is the Law of Conservation of Mass?

a) Mass can be created during a reaction

b) Mass is neither created nor destroyed in physical or chemical changes

c) The total mass of products exceeds reactants

d) Mass varies with temperature

Answer: b

What is the Law of Definite Proportions?

a) A compound contains varying proportions of elements

b) A compound always contains the same proportion of elements by weight

c) All elements are in equal proportions

d) Elements can be combined in any ratio

Answer: b

What is an Empirical Formula?

a) The formula depicting the structure of a molecule

b) The simplest whole number ratio of various atoms present in a compound

c) The molecular formula with additional elements

d) A formula that represents the phase of a substance

Answer: b

What is Molarity?

a) The number of grams of solute per liter of solution

b) The number of moles of solute per liter of solution

c) The volume of a solution in liters

d) The concentration without units

Answer: b

What are Significant Figures?

a) Digits at the end of a number

b) Digits that contribute to precision, including all non-zero digits and zeros between them

c) Any digits in a number

d) Only whole numbers in a measurement

Answer: b

What is Stoichiometry?

a) The study of molecular weights

b) The calculation of reactants and products in chemical reactions

c) A way to measure temperature changes

d) The analysis of gases only

Answer: b

What is a Limiting Reagent?

a) The fastest reacting substance

b) The reactant that is consumed first in a chemical reaction, limiting the amount of product formed

c) A reagent used just for balancing equations

d) The excess reactant in reactions

Answer: b

What is Dimensional Analysis?

a) A process of analyzing chemical properties

b) A method for converting units from one system to another

c) A way to determine chemical reactions

d) Analyzing dimensions of physical objects

Answer: b

What is Molecular Mass?

a) The mass of a single atom

b) The sum of the atomic masses of all atoms in a molecule

c) The weight of a sample in grams

d) Mass measured in pounds

Answer: b

What is Average Atomic Mass?

a) The most common mass of an element's isotope

b) The weighted average of the atomic masses of an element's isotopes

c) The total atomic mass of all isotopes combined

d) The mass of the lightest isotope

Answer: b

What is Density?

a) The weight of a substance

b) The mass of a substance divided by its volume

c) The total volume of a substance

d) The ratio between pressure and temperature

Answer: b

What is a Chemical Reaction?

a) A rapid change in the state of matter

b) A process that leads to the transformation of one set of chemical substances into another

c) A physical change of state

d) A chemical change without any reactants

Answer: b

What properties are used to distinguish between different states of matter?

a) Color

b) Density, shape, and volume

c) Temperature only

d) Mass

Answer: b

What is the primary characteristic of a solid?

a) Fixed shape and volume

b) Indefinite shape, fixed volume

c) Indefinite shape and volume

d) Gas-like behavior

Answer: a

In which state of matter do particles have the highest energy?

a) Liquid

b) Solid

c) Gas

d) Plasma

Answer: c

What happens to a substance's density as it is heated?

a) Density increases

b) Density decreases

c) Density remains constant

d) Density becomes zero

Answer: b

What is an example of a physical change?

a) Burning wood

b) Dissolving salt in water

c) Rusting iron

d) Cooking an egg

Answer: b

What is the main indication that a chemical reaction has occurred?

a) Change of state

b) Change of color or temperature and formation of gas

c) Physical mixing

d) None of the above

Answer: b

Which of the following is an endothermic reaction?

a) Combustion

b) Respiration

c) Photosynthesis

d) Rusting

Answer: c

What determines the molar mass of a compound?

a) All elements in a compound

b) Only the heaviest element

c) The sum of the atomic masses of all atoms present

d) The number of molecules

Answer: c

Which of the following statements is true about isotopes?

a) They have the same atomic number but different mass numbers

b) They have different atomic numbers

c) They have the same number of neutrons

d) They are chemically the same

Answer: a

What is the standard pressure used in calculations at STP (Standard Temperature and Pressure)?

a) 1 atm

b) 2 atm

c) 0.5 atm

d) 4 atm

Answer: a

What unit is used to measure pressure in chemistry?

a) Liter

b) Joule

c) Pascal

d) Gram

Answer: c

What does the term 'reactants' refer to in a chemical reaction?

a) The substances formed

b) The substances consumed

c) Both products and reagents

d) All elements involved

Answer: b

What does the chemical formula H2O represent?

a) Hydrogen oxide

b) Water

c) Oxygenated hydrogen

d) Both a and b

Answer: d

In a chemical equation, what does a coefficient represent?

a) The number of molecules

b) The mass of a product

c) The moles of a reactant

d) The density of a solution

Answer: a

What is the process by which gas turns into a solid called?

a) Sublimation

b) Deposition

c) Condensation

d) Evaporation

Answer: b

At what temperature does water boil at sea level?

a) 100°C

b) 90°C

c) 80°C

d) 120°C

Answer: a

Which type of bond involves the sharing of electrons?

a) Ionic bond

b) Covalent bond

c) Metallic bond

d) Hydrogen bond

Answer: b

What is the importance of a control group in an experiment?

a) It serves as a comparison to the experimental group.

b) It includes all variables.

c) It is not needed in experiments.

d) It is the same as the experimental group.

Answer: a

What is the primary function of carbohydrates in the body?

a) To provide energy

b) To build muscles

c) To aid in digestion

d) To transport nutrients

Answer: a

What kind of bond is formed when two atoms share electrons?

a) Ionic bond

b) Covalent bond

c) Metallic bond

d) Hydrogen bond

Answer: b

Which of the following is a characteristic of metals?

a) They are good insulators.

b) They are brittle.

c) They are conductive and malleable.

d) They cannot conduct electricity.

Answer: c

Which scientist is known for developing the periodic table?

a) Dmitri Mendeleev

b) Albert Einstein

c) Niels Bohr

d) John Dalton

Answer: a

What type of reaction involves the transfer of electrons?

a) Synthesis reaction

b) Decomposition reaction

c) Redox reaction

d) Double displacement reaction

Answer: c

What is the main component of cell membranes?

a) Proteins

b) Nucleic acids

c) Lipids

d) Carbohydrates

Answer: c

Which gas is produced during photosynthesis?

a) Oxygen

b) Carbon dioxide

c) Nitrogen

d) Hydrogen

Answer: a

What is the primary role of enzymes in biochemical reactions?

a) They increase the temperature of the reaction.

b) They act as catalysts to speed up the reaction.

c) They provide energy for reactions.

d) They change the product of reactions.

Answer: b

Which of the following is a non-polar solvent?

a) Water

b) Ethanol

c) Benzene

d) Acetic acid

Answer: c

What is the process by which a liquid changes into vapor?

a) Evaporation

b) Condensation

c) Sublimation

d) Liquidification

Answer: a

What does the term 'activation energy' mean?

a) The energy required for a chemical reaction to occur.

b) The energy released during a reaction.

c) The energy given off in the form of light.

d) The energy needed to raise temperature.

Answer: a

What is the process of a gas turning into a liquid called?

a) Sublimation

b) Condensation

c) Evaporation

d) Freezing

Answer: b

Which of the following is a strong acid?

a) Acetic acid

b) Hydrochloric acid

c) Citric acid

d) Carbonic acid

Answer: b

What do you call substances that speed up chemical reactions without being consumed?

a) Reactants

b) Catalysts

c) Inhibitors

d) Products

Answer: b

What does a pH of 7 indicate?

a) Acidic solution

b) Basic solution

c) Neutral solution

d) Strong acid

Answer: c

What type of bond is formed between a metal and a non-metal?

a) Ionic bond

b) Covalent bond

c) Metallic bond

d) Hydrogen bond

Answer: a

Which law states that mass in a closed system remains constant?

a) Law of Conservation of Energy

b) Law of Conservation of Mass

c) Law of Definite Proportions

d) Law of Multiple Proportions

Answer: b

What is the primary function of DNA?

a) To store genetic information

b) To catalyze reactions

c) To provide energy

d) To act as a signal

Answer: a

What happens to the pH of a solution as it becomes more acidic?

a) It increases.

b) It remains the same.

c) It decreases.

d) It turns neutral.

Answer: c

Which of the following is a property of ionic compounds?

a) They are usually gases.

b) They have low melting points.

c) They conduct electricity when dissolved in water.

d) They are soluble in non-polar solvents.

Answer: c

What is the unit for measuring energy in chemical reactions?

a) Joule

b) Newton

c) Watt

d) Pascal

Answer: a

Which process accompanies a change from a solid to a liquid?

a) Deposition

b) Freezing

c) Melting

d) Condensation

Answer: c

What is the main characteristic of a base?

a) It tastes sour.

b) It feels slippery and tastes bitter.

c) It turns blue litmus red.

d) It is usually undissolved in water.

Answer: b

What do you call a mixture that has a uniform composition throughout?

a) Heterogeneous mixture

b) Homogeneous mixture

c) Colloidal mixture

d) Suspended mixture

Answer: b

Which particle has a positive charge?

a) Electron

b) Neutron

c) Proton

d) Nucleus

Answer: c

What does the term 'halogens' refer to in chemisty?

a) Group of non-metals with low reactivity

b) Group of metals with high density

c) Group of non-metals in Group 17

d) Group of inert gases

Answer: c

What type of reaction absorbs energy from its surroundings?

a) Exothermic

b) Endothermic

c) Redox

d) Combustion

Answer: b

Which of the following is considered a trace element necessary for human health?

a) Calcium

b) Oxygen

c) Iron

d) Hydrogen

Answer: c

What type of light reaction occurs in photosynthesis?

a) Light-dependent reactions

b) Light-independent reactions

c) Photolysis

d) Electron transport chain

Answer: a

What does the term 'oxidation' refer to?

a) Gain of electrons

b) Loss of electrons

c) Gain of protons

d) Loss of protons

Answer: b

Which of the following statements is true about acids?

a) They have a pH greater than 7.

b) They turn blue litmus red.

c) They taste bitter.

d) They do not conduct electricity.

Answer: b

Which element is required for combustion to occur?

a) Nitrogen

b) Carbon

c) Oxygen

d) Hydrogen

Answer: c

Which type of energy is stored in chemical bonds?

a) Kinetic energy

b) Thermal energy

c) Potential energy

d) Magnetic energy

Answer: c

What is the term for a substance that changes color when exposed to different pH levels?

a) Indicator

b) Solute

c) Catalyst

d) Solvent

Answer: a

What does the term 'saturation' mean in a solution?

a) No solute present

b) Maximum amount of solute dissolved

c) Minimum amount of solvent

d) Mixed evenly throughout

Answer: b

What happens during the process of distillation?

a) Solids are separated by filtration.

b) Liquid is evaporated and re-condensed to separate components.

c) Chemical reactions are accelerated.

d) Solutions are diluted.

Answer: b

What do we call a solution that has more solute than can be dissolved at a given temperature?

a) Saturated solution

b) Unsaturated solution

c) Supersaturated solution

d)