Chemistry Post-test (first science test)

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

Which set of coefficients will balance this chemical equation? __PbS(s) + __O2(g) → 2PbO(s) + 2SO2(g)

2, 3

If a chemical reaction such as photosynthesis begins with 6 atoms of carbon (C), how many atoms of carbon (C) should be in the products?

6 atoms of carbon (C)

A science class is studying the states of matter. One group of students freezes 100 grams (g) of water in a cup. Another group of students melts 50 g of ice in a cup. Which of these will MOST likely occur at the end of the experiment?

Both groups will have the same mass with which they started

Which is the BEST explanation of why heat is released when wood burns?

Burning releases energy stored in chemical bonds.

How does a balanced chemical equation satisfy the Law of Conservation of Mass?

During a chemical reaction, the total amount of matter stays the same

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

Elements within a group have similar properties

Which statement BEST describes the formation of rust?

Rust results from a chemical reaction between iron and water

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

When lithium is placed in water, it floats and makes a buzzing sound as gas bubbles form. What is happening?

a chemical change

crystalline solid

a solid that consists of crystals (example: iron-nickel meteorite)

which particle type can be identified as being from a specific element?

atom

which process is MOST effective for separating sodium chloride from a saltwater solution?

evaporation

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 (Noble Gases)

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

have similar physical characteristics

Example of chemical change:

how backing soda reacts with vinegar

Which statement best explains how periods on the periodic table are organized?

increasing atomic number from left to right

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

number of protons

how do you calculate how many atoms are in one formula unit?

sum up the subscriptions

compound

two or more elements that are chemically combined