Molecules I
A molecule of H2SO4 contains many atoms.
What is 7?
Lab partners follow the instructions during their chemistry investigation very carefully. They measure 200 mL of a clear liquid into a beaker. Then they measure 50 mL of a different clear liquid into a graduated cylinder. They pour the liquid from the graduated cylinder into the beaker. The image above shows the results.
Which should the partners conclude about the two liquids?
A chemical reaction occurred when the liquids were mixed.
A student measured the mass of a candle before and after burning and found the mass to be lower after burning than before. How can this be best explained?
Some of the products were gases which escaped and were not measured.
What is the Hindenburg made of?
Doping paint, cotton, hydrogen, etc.
What is the difference between the explosion of a gas and just popping a balloon?
The explosion of a gas ___. The popping of a balloon ___.
Which of the following represents a molecule?
CO
Where was air present in the Hindenburg system?
Inside and outside.
What caused the Hindenburg explosion?
Good job! You got your points!
Juan is reading the information that came with new medicine he has to take. One of the ingredients is lactose (C12H22O11). What can Juan conclude about lactose based on the formula?
A lactose molecule contains 12 atoms of carbon.
What happens to the atoms in a chemical reaction?
They are rearranged.
Salt and sugar appear similar, but their crystals look different at the atomic level. What does this say about the molecular structures of salt and sugar?
Salt and sugar molecules contain different atoms arranged in different patterns.
What materials were in the paint of the Hindenburg?
Dope in the paint, aluminum powder, etc.
What conditions are needed for the Hindenburg to burn?
(Any answer pertaining to heat.)
Did the hydrogen cause the Hindenburg explosion?
Yes or no. Explain.
Hydrogen (H) and oxygen (O) are pure substances. Each is made of only one type of atom, but hydrogen atoms are different from oxygen atoms. Hydrogen and oxygen chemically combine to form water (H2O).
Based on this information, which statement is true?
Hydrogen and oxygen are elements, and water is a molecule.
How is the vinegar and baking soda reaction different from the Hindenburg explosion?
Explain.
A scientist melted 25 grams of solid gold to form liquid gold. Which statement best describes the mass of the liquid gold?
25 grams because the same number of atoms will be present in the liquid and solid.
In a laboratory, Selina added five drops of hydrochloric acid to a container with sodium bicarbonate (baking soda).
Which observation helps her determine whether a chemical change has taken place?
Formation of bubbles
The first part of a balanced chemical equation is shown: Cu +2AgNO3 → ______________. In order for this equation to be balanced, how many oxygen (O) atoms must be present in the products?
6
Table sugar, or sucrose, is made of carbon, hydrogen, and oxygen atoms. In nature, carbon is often a black solid, and hydrogen and oxygen are colorless gases. Why does sugar look different than the elements from which it is made?
The properties of molecules are different from the elements they are made from.
What happens when an ice cube melts in a beaker of water?
A physical change occurs because the ice changes from a solid to a liquid.
Does the metal paint make the cotton burn faster?
Explain it to me.
Based on what you know about the factors needed to make something burn, what molecule do you think would be added to propane, C3H8, to make it explode?
Oxygen.
What do scientists do to help them understand things that cannot be seen with the human eye?
Use a microscope. Get down to the molecular level.
What happens to the substances when they burn?
Create a new substance because of the chemical reaction.