Chemistry Chapter 6-7 Flashcards
What is the number of reactants in a chemical equation?
The number of different elements prior to reaction (NOT the number of atoms)
What is the difference between a complete combustion and incomplete combustion?
Complete:
It occurs when there is sufficient oxygen. It will always produce carbon dioxide, water and energy
Incomplete :
it occurs when there is insufficient oxygen; MAY produce carbon monoxide, carbon dioxide, soot, water and energy
Why shouldn’t you cook on a barbeque in an enclosed space?
Because with the insufficient amount of oxygen, carbon dioxide and carbon monoxide could be produced which are toxic in higher amounts
Using the conservation of mass, why should chemical equations be balanced?
To show that both sides of the equation have the same mass
How do you name ionic compounds vs molecular compounds?
Ionic:
- Metal/cation first
- the second element has the suffix/ending of “ide”
- EX: Sodium Chloride
Molecular:
- add prefixes to both elements
- add ide as the suffix to the SECOND element
- do NOT add mono to the first element
Define what an acid is
An acid is a subtance that contains hydrogen ions. When an acid is dissolved in water, it ionizes. This stage of an acid being dissolved in water is when tis acidic properties are noticeable. Acids have a pH below 7.
Define what a base is
A base is a compound that contains hydroxide ions to give it its basic properties. It is conductive of electricity, when dissolved in water. It has a pH greater than 7
What are the ions that give acids their acidic properties?
The hydrogen ions
What are the ions that give bases their basic properties?
Hydroxide ions
Why are acids and bases aqueous?
Because the reason why acids and bases can be described as such is because they can dissolve in water, and therefore, ionize
What happens when an acid reacts with a metal?
It produces hydrogen gas and a salt/ionic compound
What happens when a base reacts with a metal?
No reaction
What happens when an acid reacts with a carbonate?
Acids react with carbonates to produce CO2 gas.
Can acids and bases conduct electricity?
Yes, they both can when they are dissolved in water
Why do acids and bases have to be dissolved in water to conduct electricty?
Because when they dissolve, they generate ions in the solution. These ions are charge carriers
What colour is bromothymol blue in an acid and in a base?
Acid: Yellow
Base: Blue
Neutral: Green
What is the word equation for a neutralization reaction?
Acid + Base = Water and Salt
When do you put the bracket around the polyatomic ion?
When you add the ion charge of the other element to be the subscript of the polyatomic ion
What happens in a neutralization reaction?
The hydrogen ions from the acid and the hydroxide ions from the base bind together to form water. Also, their opposite charges create a salt. Ultimately, the reactions creates a solution closer to, or fully, neutral.
Does a neutralization reaction always create something completely neutral? Why?
No
- different strengths of acids and bases can cause certain components of the equation to be less effective at neutralizing the other
- different ratios should also be considered
Most ionic compounds are, acids or bases?
Bases
What colour does red litmus paper turn in a base?
What colour does blue litmus paper turn in an acid?
Red litmus paper in a base turns blue. (Blue for Base)
Blue litmus paper turns red in an acid
What are the two different types of acids and their differences?
Binary Acids:
- Composed of hydrogen and a non-metal
- always start with HYDRO
Oxyacids:
- composed of hydrogen, oxygen and a polyatomic ion
- the polyatomic ion contains oxygen (hence the name)
- does NOT start with HYDRO when pronouncing or writing
THINK: Hydrochloric acid
- you say the hydro part and Cl is NOT a polyatomic ion
What is the range of the pH scale?
0-14
Acids and bases are considered electrolytes. Why is this?
Because when they are dissolved in water, they separate into ions, which carry charges, and therefore, conduct electricity
What is proof of a chemical reaction?
- Change in temperature
- bubbles
- New odour
- precipitate
- emission of light
- change in colour
What is the purpose of the arrow in a chemical equation?
It is to indicate in which direction the chemical equation is going. It also means yields or produces
What indicates that a chemical reaction has stopped?
When the original substance is no longer present and when no changes are occurring (eg: no more gas is escaping)
Also when the rate of the reaction has slowed down or stopped
What could account for a change in mass in the product of the chemical equation?
- the fact that some of the reactant may have been released (EX: gas was released)
How does single displacement work?
A compound and a metal undergo a chemical change and the metal swaps places with the less reactive element of the compound.
What is a synthesis reaction?
It’s the chemical reaction in which atoms are combined.
Two or more reactants form one product
What is Decomposition?
Opposite of synthesis. Compounds break down into ELEMENT or smaller compounds
What is double displacement?
Elements or poly atomic ions in different compounds displace each other by changing places. THE METALS SWAP PLACES
Two compounds create two NEW compounds
What is a combustion reaction? What is the difference between a complete combustion and an incomplete combustion?
Combustion: the rapid reaction of a substance with oxygen to produce oxides.
Complete combustion: occurs when there is sufficient oxygen. The products are always carbon dioxide, water and energy.
Incomplete combustion: occurs when there is insufficient oxygen; may produce carbon monoxide, carbon dioxide, soot (solid carbon), water and energy.
What is a hydrocarbon?
An element with only hydrogen and carbon. Hydrocarbons are considered fuels because they are highly combustible and main source of energy in the world
What are the reactants and products of a complete and incomplete combustion?
Complete: hydrocarbon + oxygen gas = water + carbon dioxide + energy
Incomplete: hydrocarbon + oxygen gas = water + carbon dioxide + carbon monoxide + solid carbon + energy
- the energy is heat and light
How do you name binary acids?
Binary acids: hydrogen + non-metal
Start with the prefix of HYDRO and attach the name of a non metal with suffix ic
Ex: hydrofloric acid
How do you name oxyacids?
Oxyacids: composed of hydrogen and poly atomic ion
DO NOT write hydro, just the name of the poly atomic ion with the suffix of ic
Ex: Nitric acid
What are the ways we can remove metals from soil?
Acid leaching
- soil is revived from the site
- acids are added to dissolve the metals, then the metals are washed away
- the clean soil can be returned to its place
A cheaper way: phytoremediation
- there are plants that absorb the metals in the soil
- so these plants are places in the soil, and later are disposed of
What is the ideal pH of swimming pools?
7.2-7.6
What is the pH of our skin?
Slightly acidic
What happens in a swimming pool if pH increases too much?
The water will be irritating to the eyes and the chlorine will lose its affect which can cause microorganisms to grow
If water is too acidic it can be irritating to the eyes
Why is it important to regulate the pH of soil?
Because different plants thrive in different pH levels
Why are cleaning products basic?
Basic substances are corrosive, and therefore, are able to break down fatty and greasy deposits
Typically, food and some bodily residues are acidic. So basic cleaning products are required to break them down and remove them.
Why are acidic foods bad for the teeth?
Because their acidity dissolves the tooth enamel, causing the teeth to have less protection
How do bases react with carbonate?
No reaction
What is the difference between something aqueous and liquid?
Aqueous means a solution, in which water is the solvent. Something aqueous DISSOLVES IN WATER.
Liquid refers to something that is solely a liquid, and does no mecessarily involve water
Why put oil on a car?
Because the oil will keep the moisture away from reacting with the metal of the car, making sure that the metal will not rust
Fuels burn faster when the concentration of oxygen is increased. T or F?
Why?
True
Because for a combustion action to occur, the fuel molecules must react with oxygen. Hence, when there is more oxygen, more fuel molecules can react simultaneously
Calcium hydroxide dissolves very slowly in water. Is this a good thing when adding it to soil to make it more basic?
A good thing because it will not be washed away when it rains
Would it be a good idea to go to bed after drinking apple juice or not?
Apple juice is acidic.
It might be fine for some as its acidity may help the stomach with digestion. For others, the extra acidity, especially before bed, may cause acid reflux and heartburn
Substances that change colour depending on the acidity or basic(ness) of a substance are called BLANK
Indicators
How many elements are in an oxyacid?
3: Hydrogen, oxygen, and another metal that is bonded with oxygen to create a polyatomic ion
What is the acid in our stomach?
Hydrochloric acid
pH: 1.5
What is the purpose of antacids?
Our stomach contains hydrochloric acid, and if this acid irritates the lining of the esophagus, an antacid can neutralize the acid and relieve the pain and irritation
What is the pain in our esophagus called (due to acid)
Heart burn
What does milk of magnesia contain as a base?
Magnesium hydroxide
What do powdered antacids usually contain?
Sodium hydrogen carbonate (baking soda) as the active ingredient
What is the less common ion found in bases?
Carbonate
