Chemicals physics Flashcards
What is the definition of a mole in chemistry?
A mole is defined as 6.022 x 10^23 particles of a substance.
True or False: The atomic number of an element is the number of protons in its nucleus.
True
Fill in the blank: The unit of pressure in the International System of Units (SI) is the ______.
Pascal
What is the primary difference between an ionic bond and a covalent bond?
An ionic bond involves the transfer of electrons, while a covalent bond involves the sharing of electrons.
Which of the following is a strong acid? a) HCl b) CH3COOH c) NH3 d) H2O
a) HCl
What is Avogadro’s number?
6.022 x 10^23
True or False: The pH scale ranges from 0 to 14.
True
What is the formula for calculating density?
Density = Mass/Volume
Fill in the blank: The process of a solid turning directly into a gas is called ______.
sublimation
What is the principle behind Le Chatelier’s principle?
If a system at equilibrium is subjected to a change in concentration, temperature, or pressure, the system will adjust to counteract that change.
Which subatomic particle has a negative charge?
Electron
True or False: All elements in the same group of the periodic table have similar chemical properties.
True
What is the main component of natural gas?
Methane (CH4)
Fill in the blank: The law of conservation of mass states that mass cannot be ______ or ______ in a chemical reaction.
created; destroyed
What is the term for the energy required to break a bond in a molecule?
Bond dissociation energy
Which of the following is an example of a physical change? a) Burning wood b) Dissolving sugar in water c) Rusting iron d) Baking a cake
b) Dissolving sugar in water
What is the term for the amount of energy required to raise the temperature of 1 gram of a substance by 1 degree Celsius?
Specific heat capacity
True or False: An endothermic reaction absorbs heat from its surroundings.
True
What does the term ‘electronegativity’ refer to?
The tendency of an atom to attract electrons in a chemical bond.
What is the chemical formula for water?
H2O
Fill in the blank: The three states of matter are solid, liquid, and ______.
gas
What is the effect of temperature on the rate of a chemical reaction?
Generally, an increase in temperature increases the reaction rate.
Which gas is produced during photosynthesis?
Oxygen (O2)
True or False: A catalyst increases the activation energy of a reaction.
False
What is the term for the maximum amount of solute that can dissolve in a solvent at a given temperature?
Solubility
Which of the following is a non-metal? a) Sodium b) Chlorine c) Iron d) Magnesium
b) Chlorine
What does a chemical equation represent?
A chemical equation represents the reactants and products in a chemical reaction.
Fill in the blank: The main gas contributing to the greenhouse effect is ______.
Carbon dioxide (CO2)
What is the term for the process by which a liquid turns into vapor?
Evaporation
True or False: Isotopes of an element have the same number of protons but different numbers of neutrons.
True
What is the primary purpose of a buffer solution?
To maintain a stable pH in a solution.
Which of the following elements is a noble gas? a) Helium b) Oxygen c) Nitrogen d) Hydrogen
a) Helium
What is the process of converting a gas into a liquid called?
Condensation
Fill in the blank: The ______ is the smallest unit of an element that retains the properties of that element.
atom
What is the significance of the octet rule in chemistry?
Atoms tend to bond in such a way that they have eight electrons in their valence shell.
True or False: A solution with a pH of 7 is considered neutral.
True
What is the chemical formula for table salt?
NaCl
Which type of reaction involves the combination of two or more substances to form a single product?
Synthesis reaction
Fill in the blank: The ______ shell is the outermost shell of electrons in an atom.
valence
What is the name of the process by which plants convert sunlight into chemical energy?
Photosynthesis
True or False: The boiling point of a liquid is the temperature at which its vapor pressure equals the atmospheric pressure.
True
What is the term for a mixture that has a uniform composition throughout?
Homogeneous mixture
Which of the following is a characteristic of metals? a) Brittle b) Good conductors of heat and electricity c) Dull appearance d) Low melting points
b) Good conductors of heat and electricity
What is the primary factor that affects the solubility of a solute in a solvent?
Temperature
Fill in the blank: The law of definite proportions states that a chemical compound always contains its component elements in ______ by mass.
fixed ratio
