Elements, Compounds, and Molecules

Which set of coefficients will balance this chemical equation?

1,3

If 100 grams of vinegar and 5 grams of baking soda are poured in a container, a small amount of gas will be produced. What will the final mass of the products be if the gas is trapped in the container?

105 grams

Which of the samples shown represents an element?

2

Which set of coefficients will balance this chemical equation? PbS

2,3

Juan Carlos placed 35 grams of ice into a dry, 200-gram container. The top of the container was attached tightly. When the ice was completely melted, the student measured the mass of the container with the liquid water. What should the mass of the liquid water in the container be?

35 grams

molecule

A ______________ can be an element or a compound, consisting of one or more like atoms in an element and two or more different atoms in a compound.

Compounds

A ________________ is when one or more elements have been chemically combined together through a chemical reaction to form a new substance. An example is H2O (water). You can also count the capital letters. If there are 2 or more capital letters it is a compound.

A student performs an experiment and the results are shown below. Before: Iron filings are brown, small, and magnetic; copper sulfate crystals are blue, brittle, and not magnetic. After: The copper formed was reddish, solid, and not magnetic; iron sulfide solution was colorless and not magnetic. Which statement supports that a chemical reaction took place?

A new substance was formed.

What was observed that led to the arrangement of sixty-three already-known elements by increasing atomic weights in the periodic table?

A repetition occurs in chemical and physical properties.

Which is a compound?

Ammonia

element

An ___________ is a pure substance that cannot be broken down into any other substance. It is represented on the periodic table by a symbol. For example, O is Oxygen.

Scientists can identify an element by looking at the structure of a single

Atom

When a molecule is separated into its component parts, it forms

Atoms

physical properties

Density, Melting point, malleability

Which statement BEST describes the organization of the periodic table of the elements?

Elements within a group have similar properties.

Which of the following is a correctly written chemical equation that demonstrates the conservation of mass?

H20+CO2-H2CO3

mass & space

Matter is anything that has ____ and takes up _____

Chemical Properties

Reactivity, Flammability, Acidity

A chemical reaction separates water into hydrogen gas and oxygen gas. Which of the following statements is true about the mass of the water and the combined mass of the two gases?

The combined mass of the two gases is the same as the mass of the water.

Which of these is one similarity of the elements in the first group of the periodic table?

The elements in the group react with oxygen in similar ways.

Sodium sulfate and barium chloride react with each other to form sodium chloride and barium sulfate as shown. Which statement MOST accurately describes the mass of the reactants compared to the mass of the products?

The mass of the reactants is the same as the mass of the products.

A student is testing a solid material to determine whether it is a pure substance or a mixture. Which observation would MOST likely indicate that the material is a mixture?

The material has crystals of two different colors.

How does the concept of conservation of mass apply to chemical reactions?

The reactants and products have exactly the same atoms.

During photosynthesis, carbon dioxide and water combine according to the general equation: Why is photosynthesis a chemical reaction?

because new substances are formed

Which of these are broken down during chemical, but not physical, changes?

compounds

What physical property is characteristic of all of the elements in the group located in the rightmost column of the periodic table?

gas state at room temperature

Which of these does NOT illustrate substances reacting to form new substances?

h2o(l) - h2o(g)

Elements in the same column of the periodic table of the elements all

have similar physical characteristics

Separating carbon dioxide from a solution of carbonated water is MOST rapidly accomplished by

increasing the temperature of the carbonated water and decreasing the pressure above the surface of the carbonated water.

Which type of matter can be separated by physical means?

mixture

Which characteristic of an element determines its placement in the periodic table?

number of protons

John and Lisa collected a sample of ocean water and placed it in a jar. Within a couple of days, the water had evaporated and salt was visible at the bottom of the jar. This is an example of a

physical change.

Which compound does not contain individual molecules.

salt

A beaker contains a sample of water with a mass of 325 grams. The water in the beaker is boiled and weighed again after it cools. The new mass of the water is 305 grams. In this example of the conservation of matter in physical changes,

the mass of the water was 305 grams and the mass of the water vapor was 20 grams

Where are the most reactive nonmetals located on the periodic table?

the second column from the right side of the table

Where are the most reactive metals located on the periodic table?

the uppermost complete row of the table