Chemistry Exam 2025 Questions and Correct answers Graded A+ Verified

Which field of science studies the composition and structure of matter? - Correct Answer-chemistry Which of the following would a chemist be most likely to study? a. a leaf floating on water c. a leaf being blown by the wind b. a leaf changing color in autumn d. a leaf being eaten by insects - Correct Answer-a leaf changing color in autumn . Which of the following best describes an example of pure chemistry? a. testing the effects of lower concentrations of a drug on humans b. studying chemicals containing carbon c. developing a cure for osteoporosis d. finding an antidote for a new strain of virus - Correct Answer-studying chemicals containing carbon Which of the following statements is false? a. Knowledge of chemistry allows the public to make informed decisions. b. Studying chemistry ensures that officials make correct choices in funding technology. c. Knowledge of chemistry helps prepare people for careers in soil science. d. Chemistry explains many aspects of nature. - Correct Answer-. b. Studying chemistry ensures that officials make correct choices in funding technology. Which of the following is NOT an example of chemistry research in the main area of energy? a. producing hook-and-loop tape b. determining the usefulness of oil from soybean plants c. developing rechargeable batteries d. studying the effects of insulation - Correct Answer-producing hook-and-loop tape One characteristic of a scientific theory is that ____. - Correct Answer-it can never be proved Which step in the scientific method requires you to use your senses to obtain information? - Correct Answer-making an observation CHEM CHEM . How do conceptual problems differ from numeric problems? - Correct Answer-Solutions to conceptual problems normally do not involve calculations. Which of the following is NOT an example of matter? a. air c. smoke b. heat d. water vapor - Correct Answer-heat All of the following are physical properties of matter EXCEPT ____. a. mass c. melting point b. color d. ability to rust - Correct Answer-ability to rust Which of the following are considered physical properties of a substance? - Correct Answer-color and odor malleability and hardness melting and boiling points (All of the above) A vapor is which state of matter? - Correct Answer-gas Which state of matter has a definite volume and takes the shape of its container? - Correct Answer-liquid Which state of matter is characterized by having an indefinite shape, but a definite volume? - Correct Answer-liquid Which state of matter is characterized by having a definite shape and a definite volume? - Correct Answer-solid Which state of matter expands when heated and is easy to compress? - Correct Answer-gas All of the following are physical properties of a substance in the liquid state EXCEPT ____. a. indefinite volume c. not easily compressed b. definite mass CHEM CHEM d. indefinite shape - Correct Answer-indefinite volume . Which of the following is a physical change? a. corrosion c. evaporation b. explosion d. rotting of food - Correct Answer-evaporation . Which of the following is a heterogeneous mixture? a. air c. steel b. salt water d. soil - Correct Answer-soil . Which of the following is true about homogeneous mixtures? a. They are known as solutions. b. They consist of two or more phases. c. They have compositions that never vary. d. They are always liquids. - Correct Answer-They are known as solutions. An example of a homogeneous mixture is ____ - Correct Answer-stainless steel Which of the following items is NOT a compound? a. baking soda c. sucrose b. salad dressing d. table salt - Correct Answer-salad dressing Which of the following is true about compounds? a. They can be physically separated into their component elements. b. They have compositions that vary. c. They are substances. d. They have properties similar to those of their component elements. - Correct Answer They are substances. What distinguishes a substance from a mixture? - Correct Answer-Mixtures can be separated physically, while substance cannot. CHEM CHEM The first figure in a properly written chemical symbol always is ____. - Correct Answer capitalized Which of the following is used for chemical symbols today? - Correct Answer-letters The chemical formula of a compound does NOT indicate the ____. - Correct Answer how elements are joined in the compound In the chemical reaction in which sucrose is heated and decomposes to form carbon dioxide and water, which of the following is a reactant? - Correct Answer-sucrose What must occur for a change to be a chemical reaction? - Correct Answer-There must be a change in chemical properties. Which of the following does NOT involve a physical change? a. mixing c. grinding b. melting d. decomposing - Correct Answer-decomposing Which of the following processes does NOT involve a change in chemical properties? a. rusting c. boiling b. fermenting d. burning - Correct Answer-boiling A chemical change occurs when a piece of wood ____ - Correct Answer-decays What must be done to be certain that a chemical change has taken place? - Correct Answer-Check the composition of the sample before and after the change When paper turns yellow-brown upon exposure to sunlight, what type of change is likely taking place? - Correct Answer-a chemical change Which of the following indicates that a chemical change has happened during cooking? a. The food darkens. b. Bubbles form in boiling water. c. Butter melts. d. Energy is transferred from the stove to a pan. - Correct Answer-The food darkens. What happens to matter during a chemical reaction? - Correct Answer-Matter is neither destroyed or created. Which of the following is true for all chemical reactions? a. The total mass of the reactants increases. CHEM CHEM b. The total mass of the products is greater than the total mass of the reactants. c. The total mass of the products is less than the total mass of the reactants. d. The total mass of the reactants equals the total mass of the products. - Correct Answer-The total mass of the reactants equals the total mass of the products. Which of the following measurements contains two significant figures? a. 0.004 00 L c. 0.000 44 L b. 0.004 04 L d. 0.004 40 L - Correct Answer-0.000 44 L When a test instrument is calibrated, does its accuracy, precision, or reliability improve? - Correct Answer-accuracy Which group of measurements is the most precise? (Each group of measurements is for a different object.) a. 2 g, 3 g, 4 g c. 2 g, 2.5 g, 3 g b. 2.0 g, 3.0 g, 4.0 g d. 1 g, 3 g, 5 g - Correct Answer-2 g, 2.5 g, 3 g Which of the following measurements is expressed to three significant figures? a. 0.007 m c. 7.30 mc 10mc km b. 7077 mg d. 0.070 mm - Correct Answer-7.30mc g 10m km How many significant figures are in the measurement 0.003 4 kg? - Correct Answer-two How many significant figures are in the measurement 40,500 mg? - Correct Answer three How many significant figures are in the measurement 811.40 grams? - Correct Answer five Express the sum of 1111 km and 222 km using the correct number of significant digits. - Correct Answer-1333 km Express the product of 2.2 mm and 5.00 mm using the correct number of significant digits. - Correct Answer-11 mm CHEM CHEM What is the measurement 1042 L rounded off to two significant digits? - Correct Answer-1.0 mc 10mc L What is the metric system prefix for the quantity 0.000 001 - Correct Answer-micro- Which of the following volumes is the smallest? a. one microliter c. one milliliter b. one liter d. one deciliter - Correct Answer-one microliter What is the temperature of absolute zero measured in C? - Correct Answer--273nC Which temperature scale has no negative temperatures? - Correct Answer-Kelvin What is the boiling point of water in kelvins? - Correct Answer-373 K . The weight of an object ____. - Correct Answer-depends on its location If the temperature changes by 100 K, by how much does it change in C? - Correct Answer-100 C What is the quantity 0.0075 meters expressed in centimeters? - Correct Answer-0.75 cm A train travels at a speed of 30 miles per hour. If 1 mile = 1.6 kilometers, how fast is the train traveling in kilometers per minute? - Correct Answer-0.8 km/min The density of mercury is 5,427 kg/(m3). If the density of water is 1.0 g/mL, will mercury float or sink in water? - Correct Answer-Mercury will sink because the density of mercury is 5.427 g/mL, which is greater than the 1.0 g/mL density of water. Which of the following equalities is NOT correct? Use the table above to help you. a. 100 cg = 1 g c. 1 cm = 1 mL b. 1000 mm = 1 m d. 10 kg = 1 g - Correct Answer-10 kg = 1 g A cubic meter is about the same as the volume occupied by a ____. - Correct Answer washing machine . CHEM CHEM What is the density of an object having a mass of 8.0 g and a volume of 25 cm^3 - Correct Answer-0.32 g/cm^3 What is the volume of 45.6 g of silver if the density of silver is 10.5 g/mL? - Correct Answer-4.34 mL . If the temperature of a piece of steel decreases, what happens to its density? - Correct Answer-The density increases. Dalton's atomic theory included which idea? - Correct Answer-Atoms of the same element are always identical. Which of the following is NOT a part of Dalton's atomic theory? a. All elements are composed of atoms. b. Atoms are always in motion. c. Atoms of the same element are identical. d. Atoms that combine do so in simple whole-number ratios - Correct Answer-Atoms are always in motion. Which of the following was originally a tenet of Dalton's atomic theory, but had to be revised about a century ago? a. Atoms are tiny indivisible particles. b. Atoms of the same element are identical. c. Compounds are made by combining atoms. d. Atoms of different elements can combine with one another in simple whole number ratios. - Correct Answer-Atoms are tiny indivisible particles. . The comparison of the number of atoms in a copper coin the size of a penny with the number of people on Earth is made to illustrate which of the following? - Correct Answer-that atoms are very small Dalton hypothesized that atoms are indivisible and that all atoms of an element are identical. It is now known that ____. - Correct Answer-atoms are divisible Which of the following is true about subatomic particles? a. Electrons are negatively charged and are the heaviest subatomic particle. b. Protons are positively charged and the lightest subatomic particle. c. Neutrons have no charge and are the lightest subatomic particle. d. The mass of a neutron nearly equals the mass of a proton. - Correct Answer-The mass of a neutron nearly equals the mass of a proton. CHEM CHEM What is the relative mass of an electron? - Correct Answer-1/1840 the mass of a hydrogen atom Which of the following is correct concerning subatomic particles? a. The electron was discovered by Goldstein in 1886. b. The neutron was discovered by Chadwick in 1932. c. The proton was discovered by Thomson in 1880. d. Cathode rays were found to be made of protons. - Correct Answer-The neutron was discovered by Chadwick in 1932 As a consequence of the discovery of the nucleus by Rutherford, which model of the atom is thought to be true? - Correct Answer-Electrons are distributed around the nucleus and occupy almost all the volume of the atom. . The atomic number of an element is the total number of which particles in the nucleus? - Correct Answer-protons In which of the following sets is the symbol of the element, the number of protons, and the number of electrons given correctly? a. In, 49 protons, 49 electrons c. Cs, 55 protons, 132.9 electrons b. Zn, 30 protons, 60 electrons d. F, 19 protons, 19 electrons - Correct Answer-In, 49 protons, 49 electrons Using the periodic table, determine the number of neutrons in O. - Correct Answer-8 How many protons, electrons, and neutrons does an atom with atomic number 50 and mass number 125 contain? - Correct Answer-50 proton