Teste Ia Flashcards
What is the chemical formula for water?
H2O
True or False: The pH scale ranges from 0 to 14.
True
Fill in the blank: The process of a solid turning directly into a gas is called _______.
sublimation
What is the main gas produced during cellular respiration?
Carbon dioxide (CO2)
Which element has the atomic number 6?
Carbon
What is the term for a substance that increases the rate of a chemical reaction without being consumed?
Catalyst
True or False: Acids have a pH less than 7.
True
What is the name of the process by which plants convert sunlight into chemical energy?
Photosynthesis
Which gas is commonly known as laughing gas?
Nitrous oxide (N2O)
Fill in the blank: The __________ is the smallest unit of an element that retains the properties of that element.
atom
What type of bond involves the sharing of electron pairs between atoms?
Covalent bond
What is the molar mass of carbon dioxide (CO2)?
44 g/mol
Which type of reaction involves a substance breaking down into simpler substances?
Decomposition reaction
True or False: All chemical reactions involve a change in energy.
True
What is the primary component of natural gas?
Methane (CH4)
Fill in the blank: The __________ law states that mass is neither created nor destroyed in a chemical reaction.
law of conservation of mass
What is the term for the amount of solute that can dissolve in a given amount of solvent at a specific temperature?
Solubility
Which element is represented by the symbol ‘Na’?
Sodium
What is the difference between an ionic bond and a covalent bond?
Ionic bonds involve the transfer of electrons, while covalent bonds involve sharing electrons.
True or False: Noble gases are highly reactive.
False
What is the term for a solution that contains more solute than it can theoretically hold at a given temperature?
Supersaturated solution
Which acid is commonly found in vinegar?
Acetic acid (CH3COOH)
Fill in the blank: The __________ is a measure of the concentration of hydrogen ions in a solution.
pH
What is the primary purpose of a buffer in a chemical system?
To maintain a stable pH
Which type of reaction occurs when an acid and a base react to form water and a salt?
Neutralization reaction
What is the term for the energy required to initiate a chemical reaction?
Activation energy
True or False: The atomic number of an element is equal to the number of protons in its nucleus.
True
What is the most abundant gas in the Earth’s atmosphere?
Nitrogen (N2)
Fill in the blank: A __________ is a substance that donates protons (H+) in a chemical reaction.
Bronsted acid
What is the term for the process of a liquid turning into a gas?
Evaporation
Which element is a liquid at room temperature?
Bromine (Br)
What is the chemical formula for table salt?
NaCl
True or False: All metals are good conductors of electricity.
False
What is the process by which a gas turns into a liquid?
Condensation
Fill in the blank: The __________ is the part of the atom that contains protons and neutrons.
nucleus
What is the term for the temperature at which a liquid turns into a gas?
Boiling point
Which type of radiation has the highest energy?
Gamma radiation
What is the principle behind chromatography?
Separation of components based on their movement through a medium
True or False: A strong acid completely dissociates in water.
True
What is the molecular formula for glucose?
C6H12O6
Fill in the blank: The __________ is the measure of the randomness or disorder of a system.
entropy
What is the term for the energy stored in chemical bonds?
Chemical potential energy
Which type of bond is formed by the attraction between positively and negatively charged ions?
Ionic bond
What is the significance of the periodic table?
It organizes elements based on their properties and atomic structure.
True or False: Isotopes of an element have the same number of neutrons.
False
What is the term for the amount of heat energy required to raise the temperature of 1 gram of a substance by 1 degree Celsius?
Specific heat capacity
