Question

Choose the best answer that matches each statement below. Some choice may be used more than once, and some choices may not be used at all. Each question has one correct answer.

A _____ is formed when two or more elements are combined in a chemical reaction.
First to develop and atomic theory.
A _____ change results in the formation of a new substance.
He is credited with the discovery of the proton and electron.
______ cannot be broken down any further by chemical means.
This can be separated using techniques such as filtration and distillation.
The nucleus of an atom has a ______ charge.
To determine the number of _____ we subtract the atomic number from the atomic mass.
Protons and _____ have the opposite charges.
______ energy is the energy of position.
He developed the energy levels K, L, M and N.
A reaction that results in a production of heat is called an _______ reaction.
The mass of the atom is made up of the mass of the proton and _______.
Dissolving sugar in water is an example of a _______ change.
Wood rotting is an example of a _______ change. Answer choices are: Liquids(s), Compound(s), Dalton, Electron (s), Kinetic, Chemical Change, Proton(s), Gas(es), Thomson, Endothermic, Mixture(s), Exothermic, Solids(s), Neutron(s), Positive, Potential, Physical Change, Negative, Element, Bohr

Answer 1

A Compound is formed when two or more elements are combined in a chemical reaction.

First to develop and atomic theory. Dalton

A chemical change results in the formation of a new substance. Two substances are said to be different if they have different chemical composition.

He is credited with the discovery of the proton and electron. Thomson Note: The discovery of proton is credited to Rutherford (see gold-foil experiment).

Element cannot be broken down any further by chemical means.

This can be separated using techniques such as filtration and distillation. Mixture Mixture, being a group of chemically distinct substances put together, can be separated by physical methods like filtration, distillation, etc.

The nucleus of an atom has a _positive charge. The neutron in nucleus is electrically neutral. Negatively charged electrons are positioned outside the nucleus in orbits.

To determine the number of neutron we subtract the atomic number from the atomic mass. Atomic mass = Number of proton + neutron. Atomic number = number of protons

Protons and electrons have the opposite charges.

_Potential energy is the energy of position.

He developed the energy levels K, L, M and N. Bohr

A reaction that results in a production of heat is called an exothermic reaction. Endothermic reactions absorb heat.

The mass of the atom is made up of the mass of the proton and neutron._______

Dissolving sugar in water is an example of a physical change. Solvation of sugar is a physical change because it does not affect the chemical properties of sugar. Moreover, sugar can be isolated in pure form (as it was originally) by application of physical methods, say boiling the solution.

Wood rotting is an example of a chemical change. A chemical change alters the original nature of the substance. For example, during rotting, cellulose in wood (originally) is degraded into its monomer glucose.