CHE 106 Study Guide - Final Guide: Ernest Rutherford, Dmitri Mendeleev, Ionic Compound

In 1808, John Dalton proposed a series of statements regarding the atom that became known as Dalton's postulates or Dalton's atomic theory. Since Dalton's original proposal, some of the statements have been updated or changed due to new discoveries. Which of the following statements was not a part of Dalton's original atomic theory? Atoms cannot be created or destroyed in a chemical reaction. Different elements have atoms of different masses and properties. Atoms of the same element have the same size, mass, and structure. Matter is comprised of small particles called atoms. All four statements are part of Dalton's original atomic theory.

Which of the following statements is FALSE according to Dalton's Atomic Theory? A) An atom of nitrogen can be broken down into smaller particles that will still have the unique properties of nitrogen. B) Atoms of sodium do not change into another element during chemical reaction with chlorine. C) Atoms combine in simple whole number ratios form compounds. D) All atoms of chlorine have identical properties that distinguish them from other elements. E) One carbon atom will combine with one oxygen atom to form a molecule of carbon monoxide4. In a chemical reaction, matter is neither created or destroyed. Which law does this refer to? A) Law of Definite Proportions B) Law of the Conservation of Mass C) First Law of Thermodynamics D) Law of Modern Atomic Theory E) Law of Multiple Proportions What is the mass of 0.500 mol of dichlorodifluoromethane, CCl_2 F_2? A) 121 g B) 242 g C) 4.14 times 10^-3 g D) 60.5 g How many millimoles of Ca(NO_3)_2 contain 4.78 times10^22 formula units of Ca(NO_3)_2? The molar mass of Ca(NO_3)_2 is 164.10 g/mol. A) 20.7 mmol Ca(NO_3)_2 B) 79.4 mmol Ca(NO_3)_2 C) 57.0 mmol Ca(NO_3)_2 D) 12.6 mmol Ca(NO_3)_2 E) 13.0 mmol Ca(NO_3)_2 Identify the compound with covalent bonds. A) NaCl B) Kr C) Li D) CH_4 E) KBr If the walls in a room are 955 square feet in area, and a gallon of paint covers 15 square yards, how many gallons of paint are needed for the room? (3 ft = 1 yd) A) 24 gallons B) 47 gallons C) 21 gallons D) 7.1 gallons E) 2.3 gallons Identify a solid. A) no definite shape and definite volume B) no definite shape and no definite volume C) definite volume and definite shape D) definite volume and no definite shape How many Fe atoms are contained in 787 g of Fe? A) 5.90 times 10^25 Fe atoms B) 7.09 times 10^21 Fe atoms C) 4.27 times 10^22 Fe atoms D) 4.18 times 10^24 Fe atoms E) 8.49 times 10^24 Fe atoms Barium belongs to the ______ group of the periodic table. A) alkali metal B) alkaline earth metal C) noble gas D) halogen

Chemical Reactions and Equations Learning objectives To observe physical and chemical properties associated with chemical changes To be able to give evidence for the occurrence of a chemical reaction To write a balanced chemical equation To identify areaction as a combination, decomposition, precipitation, single or double replacement, or combustion reaction ntroduction When a substance undergoes a physical change, it changes its appearance but not its composition. For example, when ice melts to form water, it undergoes a physical change from solid to liquid. In a chemical change, the composition of a substance is changed to give a new substance with different physical and chemical properties. For example, when silver tarnishes, the shiny silver (Ag) changes to a dull gray silver sulfide (AgaS). Not only has the chemical formula changed from Ag to Agus, but also the physical properties (shininess) of the substance have changed. Some examples of physical and chemical changes are listed in Table 1 below. Table 1. Comparison of Physical and Chemical Changes Examples of Physical changes Examples and Evidence of Chemical Changes Change in state (melting, freezing, evaporating Formation of a gas (bubbles) subliming) Formation of a solid (precipitate) Change in size Tearing Change in Color Heat is given off or absorbed A solid dissolving in a solvent In a chemical reaction, atoms in the reactants are rearranged to produce new combinations of atoms in the products. However, the total number of atoms of each element in the reactants is equal to the total number of atoms in the products. This is true according to the Law of Conservation of Mass, which states that the total mass remains constant during a chemical reaction. In other words, matter cannot be created or destroyed in a chemical reaction. In a chemical equation, the reactants are shown on the left and the products are on the right. An arrow in between indicates that a chemical reaction occurs. Finally, the physical state of each compound is designated in parentheses after the chemical formula. Solid, liquid, gas, and aqueous (dissolved in water) are shown as(s,(n,(g), and (aq), respectively.