Chapter 2

Which of the following statements correctly describe a mixture? (a) a mixture can vary in its composition (b) a mixture may contain both elements and compounds (c) the components of a mixture must be separated by chemical means (d) a mixture is not considered a pure substance

(a) a mixture can vary in its composition (b) a mixture may contain both elements and compounds (d) a mixture is not considered a pure substance

Which of the following statements correctly describe an element? (a) an element may consist of two or more of the same atoms bonded together (b) an element can be broken down into simpler substances (c) the properties of an atom of a specific element depend on the source of that element (d) an element cannot contain bonded atoms (e) an element consists of only one kind of atom

(a) an element may consist of two or more of the same atoms bonded together (e) an element consists of only one kind of atom

In a given chemical compound, the compound ___________ are present in ___________ proportions by mass, regardless of the source of the compound. (a) elements; fixed (b) compounds; fixed (c) compounds;equal (d) elements; equal

(a) elements; fixed

During a chemical reaction, the total _______ of the substances present does not change. The number of substance may change, but the total amount of matter present _______. (a) mass; remains unchanged (b) number; remains unchanged (c) mass; increases (d) number; increases

(a) mass; remais unchanged

Which of the following options correctly describe DALTONS ATOMIC THEORY? (a) atoms combine randomly to form a given compound (b) all matter consists of atoms (c) atoms of the same element are identical (d) compounds result from the combination of a specific ratio of atoms of different (e) atoms of one element can be converted into atoms of another element

(b) all matter consists of atoms (c) atoms of the same element are identical (d) compounds result from the combination of a specific ratio of atoms of different

Match each of the following experiment with the information contributed to the nuclear model of the atom. Thomson's experiments with cathode rays Milikan's oil drop experiments Rutherford's gold-foil experiment The discovery of the nuclear of the atom The discovery that toms can be divided into smaller particles The determination or the charge on a single electron

Thomson's experiments with cathode rays — The discovery that toms can be divided into smaller particles Milikan's oil drop experiments — The determination or the charge on a single electron Rutherford's gold-foil experiment — The discovery of the nuclear of the atom

(T/F): After the completion of a chemical reaction, the number of substances may have changed but the amount of matter remains constant. True False

True

Daltons atomic theory stated that matter consists of tiny indestructible particles called _____________, which combine in definition ratios to form ___________.

atoms; compounds

A molecule is an independent structure composed of two or more atoms chemically _________ together. A molecule composed of two atoms of same element is called a(n) __________ molecule.

bonded; diatomic

Most electrons occur in compounds combined with other elements by forming chemical __________, which are formed by the interaction of the __________ of the atoms involved.

bonds; electrons

Mass is conserved in a chemical reaction. This observation is reflected in Daltons postulate that atoms cannot be ___________ or destroyed, or changed into other types of atoms. Since each type of atom has its own __________ atomic mass, the total mass cannot change in a chemical reaction.

created; fixed

Thompson's experiment with cathode rays determined that atoms contained even smaller particles called ________, which have a ________ charge.

electrons; negative

A compound consists of two or more different ______________ that are chemically bonded together in fixed proportions. A compound can be broken down into simpler substances, a process that involves a(n) _______________ chemical change.

elements; chemical

Each element in a given compound comprises a fixed fraction or prevent by ___________ of a compound. This observation is summarized by the law of definite __________.

mass; composition

An atom is composed of a very dense central ____________ containing __________, which are positively charged and neutrons, which have ______________ electrical charge.

nucleus, protons, neutral

An ionic compound is formed when ions of __________ charge attract. An ionic compound is ________ overall even though it contains charged particles; therefore it must contain equal numbers of positive and negative _______.

opposite; neutral; charges

An element is the simplest form of matter that has unique ___________ and chemical properties. An element consists of only one kind of _________.

physical; atom

Which of the following statements correctly describe the observations that led to the development of the NUCLEAR MODEL of the atom? (a) Milikan determined the charge on a portón (b) the discovery of cathode rays led to an understanding that the atom contains smaller particles (c) the conversation of mass led scientists to infer that atoms are indivisible (d) Rutherford determined that the main mass of the atom is concentrated in a central region (e) Thomson measured the mass/ charge ratio for an electron

(b) the discovery of cathode rays led to an understanding that the atom contains smaller particles (d) Rutherford determined that the main mass of the atom is concentrated in a central region (e) Thomson measured the mass/ charge ratio for an electron

A mixture contains _____________ or more different substances. A mixture is NOT a pure substance, and to components can be separated by __________ means. (a) one;chemical (b) two;physical (c) one; physical (d) two; chemical

(b) two;physical

Which of the following statements correctly defined a molecule? (a) "molecule" is another word for "atom" (b) a molecule is the basic unit of a compound (c) a molecule is an independent structure consisting of two or more atoms covalently bonded together (d) a molecule is a substance consisting of two or more different elements chemically bonded together

(c) a molecule is an independent structure consisting of two or more atoms covalently bonded together

Water (H2O) contains 8.0g for every 1.0g of H and hydrogen peroxide (H2O2) contains 16.0g O for every 1.0g of H. Therefore, the ratio of the masses of oxygen that combine with a fixed amount if hydrogen in the two compounds in a small whole number ratio of 2:1. This is an example of the law of __________. (a) mass action (b) constant composition (c) multiple proportions (d) mass conservation

(c) multiple proportions