Science Practice Questions PDF

The law of conservation of mass states that mass cannot be \_\_\_\_\_\_\_\_\_\_ or \_\_\_\_\_\_\_\_\_\_ in a chemical reaction. Created, Destroyed A reaction in which two or more substances combine to form a new compound is called a \_\_\_\_\_\_\_\_\_\_ reaction. Synthesis A reaction in which a co...

The law of conservation of mass states that mass cannot be \_\_\_\_\_\_\_\_\_\_ or \_\_\_\_\_\_\_\_\_\_ in a chemical reaction. Created, Destroyed A reaction in which two or more substances combine to form a new compound is called a \_\_\_\_\_\_\_\_\_\_ reaction. Synthesis A reaction in which a compound breaks down into two or more simpler substances is called a \_\_\_\_\_\_\_\_\_\_ reaction. Decomposition A reaction in which one element replaces another in a compound is called a \_\_\_\_\_\_\_\_\_\_ reaction. Single-displacement A reaction in which ions from two compounds exchange places to form two new compounds is called a \_\_\_\_\_\_\_\_\_\_ reaction. Double-displacement The energy needed to start a chemical reaction is called \_\_\_\_\_\_\_\_\_\_ energy. Activation A substance that increases the number of hydronium ions when dissolved in water is called an \_\_\_\_\_\_\_\_\_\_. Acid A substance that increases the number of hydroxide ions when dissolved in water is called a \_\_\_\_\_\_\_\_\_\_. Base A reaction between an acid and a base that produces a salt and water is called a \_\_\_\_\_\_\_\_\_\_ reaction. Neutralization A solution with a pH below 7 is classified as \_\_\_\_\_\_\_\_\_\_. Acidic A solution with a pH above 7 is classified as \_\_\_\_\_\_\_\_\_\_. Basic An organic compound that contains only carbon and hydrogen is called a \_\_\_\_\_\_\_\_\_\_. Hydrocarbon A long chain of amino acids forms a \_\_\_\_\_\_\_\_\_\_. Protein The nucleic acid that carries genetic information in cells is called \_\_\_\_\_\_\_\_\_\_. DNA A radioactive particle consisting of two protons and two neutrons is called an \_\_\_\_\_\_\_\_\_\_ particle. Alpha The time required for half of a radioactive substance to decay is called its \_\_\_\_\_\_\_\_\_\_. Half-life Gamma radiation consists of high-energy \_\_\_\_\_\_\_\_\_. Electromagnetic waves What happens to mass during a chemical reaction? Mass is conserved; the total mass of reactants equals the total mass of products. How can you tell if a chemical reaction is occurring? By observing signs such as gas production, color change, temperature change, or precipitate formation. What is the difference between a catalyst and an inhibitor? A catalyst speeds up a reaction, while an inhibitor slows it down. Why do ionic compounds have high melting points? Because the strong electrostatic forces between oppositely charged ions require a lot of energy to break. What happens when an acid and a base react? They undergo neutralization, forming a salt and water. How does pH relate to the concentration of hydronium ions? A lower pH indicates a higher concentration of hydronium ions, making the solution more acidic. What are two examples of organic molecules essential to life? Proteins and nucleic acids. Why do radioactive elements decay? Their nuclei are unstable and break down into more stable forms, releasing radiation. How can half-life be used to determine the age of an object? By measuring the remaining amount of a radioactive isotope and comparing it to its known half-life. What are the three types of nuclear radiation? Alpha particles, beta particles, and gamma rays. The time required for half of a radioactive isotope to decay is called its \_\_\_\_\_\_\_\_\_\_. Half-life The process by which a large nucleus splits into two smaller nuclei, releasing energy, is called \_\_\_\_\_\_\_\_\_\_. Nuclear fission The process in which small nuclei combine to form a larger nucleus, releasing energy, is called \_\_\_\_\_\_\_\_\_\_. Nuclear fusion A continuous series of nuclear fission reactions is called a \_\_\_\_\_\_\_\_\_\_. Nuclear chain reaction The part of a nuclear power plant that absorbs excess neutrons to control the reaction is called a \_\_\_\_\_\_\_\_\_\_. Control rod The space around a charged object in which an electric force is exerted is called an \_\_\_\_\_\_\_\_\_\_. Electric field The force of attraction or repulsion between charged particles is called \_\_\_\_\_\_\_\_\_\_. Electric force A material through which charges can move freely is called a \_\_\_\_\_\_\_\_\_\_. Conductor A material that does not allow charges to move freely is called an \_\_\_\_\_\_\_\_\_\_. Insulator The loss of static electricity as electric charges move off an object is called \_\_\_\_\_\_\_\_\_\_. Electric discharge The rate at which charges pass through a given point is called \_\_\_\_\_\_\_\_\_\_. Electric current The opposition to the flow of electric charge in a material is called \_\_\_\_\_\_\_\_\_\_. Resistance A device that converts chemical energy into electrical energy is called a \_\_\_\_\_\_\_\_\_\_. Cell