physical and chemical changes
A solution of salt water is boiled. The water evaporates and solid salt remains.
The salt and the water have both undergone physical changes.
The esophagus is the tube that connects the mouth to the stomach. Heartburn occurs when some of the stomach juices flow backwards up the esophagus. To help relieve heartburn, a person should take medicine that is
basic
All atoms of the same element have the same number of ___________, which is called the atomic number :)
protons
do metals typically have dense solids with a shiny luster.
Yes:)
what chemical changes can be reversed
water when frozen and melted
A plant uses the energy from sunlight to create oxygen and glucose from carbon dioxide and water. What change is made
A chemical change has occurred because new compounds have been produced
An element is made up of??
only one type of atom
How are elements arranged in the periodic table?
atomic number
Metalloids are not elements true of false
FALSEEE
what is a compound made of
two or more different chemical elements (types of atoms, like Hydrogen, Oxygen, Carbon) that are chemically bonded together in a fixed ratio
Roads often have to be repaved because they crack over time. Sometimes this cracking is due to the fact that the roads (as well as other objects) have a tendency to expand when heated and contract when cooled. This is an exp of?
physical changes
True or false the properties of a compound are different than the properties of its elements.
True
true or false is chlorine (Cl) a nonmetal?
TRUEEE
nonmelats tend to have low densities, a dull luster, low melting points, and do not conduct electricity true or false
truee
what paper tells you if its an acid or a base
litums paper
A piece of metal is dropped into a solution of acid. Using a sharp probe, the metal is broken into smaller pieces while in the solution. Also while in the solution, some of the metal reacts, producing hydrogen gas. What change is made
Physical and chemical changes have occurred.
is CO a compound?
yes it is :)
true or false along each row of the periodic table,atomic mass is the same for all elements in the row.
false
what do nonmetals tend to form
Nonmetals tend to form ionic bonds with metals and covalent bonds with other nonmetals
what changes happen when you light a flame
chemical
mix two chemicals together in a beaker. The chemicals change color, and the beaker heats up quickly. What kind of change happend
chemical change
what is the safest way to determine if something is an acid?
use litmus paper
why was the periodic table made
It provides a powerful tool for studying the elements and how they combine.
Metals form what type of bonds
Metals most often form ionic bonds with nonmetals and metallic bonds with metals
is turning on a light a physical or chemical change
Physical change