Science Quiz 3 QT

OXIDATION

A chemical combination of oxygen with other substances forming oxides

REDUCTION

The opposite of oxidation wherein oxygen is extracted from a compound

NEUTRALIZATION

A reaction between an acid and a base forming salt and water

HYDROLYSIS

The opposite of the neutralization wherein the reaction between the salt and water forming an acid and a base

Fermentation

Is a process that result in the production of an alcohol caused by enzymes that are being produced by the bacteria and other organisms on organic substances

Law of Conservation of Mass

This law is also known as Lomonosov-Lavoisier, states that in a closed system the total mass of substances before a chemical reaction is equal to the total mass of the products after the reaction, implying mass is neither created nor destroyed during a chemical process but is conserved

Law of definite composition

This law was first observed by french chemist Joseph Louis Proust. The law of definite composition also known as the constant composition states elements combines to form compounds which always contain exactly the same proportion of elements by mass.

Law of multiple proportion

This law also known as Dalton's law was named after Charles Dalton is states that when two elements form multiple compounds the ratio of masses of one element that combines with a fixed mass of the other element can be expressed as small whole numbers

Chemical reactions

Are classified to allow the chemist to predict the possible products

Reactions

Can be classified into four types according to how they occur

Combination or Synthesis reaction

Two or more substances react to form one product (AB)

Analysis or Decomposition Reaction

If something decomposes, it break down into smaller parts

Decomposition reaction

Is a reaction in which a single compound is broken down into two or smaller compounds or elements. This reaction is known to be the reverse of the combination reaction

Single-Replacement (Substitution Reaction)

an element from its molecular form (most of them are metals) displaces an element that is part of a compound. The reactant in this reaction are always one element and one compound. The general form for this reaction is A + BX→AX + B where BX and AX are generall ionic compounds and A and B are elements in their free states. Notice that the atom represented by the letter X switches its partner

Singe-replacement (substitution reaction)

The most common type of this reaction is one in which metal ion replaces another metal. ion in a solution. To do so, the free metal must be more active than the metal that is in the solution

Double-replacement (metathesis reaction)

atoms or ions from two different compounds replace each other. An identifying characteristic of this reaction is the presence of two compounds as reactants and two compounds as products. The reactants in this reaction are generally ionic compounds.

AX + BY AY + BX

Notice that in this type of equation, the two atoms or ions represented by the letters X and Y "switch partners".

Chemical equation

Is used to illustrate a chemical reaction using symbols, formulas, and signs.

Chemical equation

It is the chemists’ shorthand for describing the sequence of a chemical reaction

Chemical equation

Helps us understajd the substances involved, their quantities, and the changes that occur during the reaction

Word equation and chemical equation

Two types of chemical equations?

Word Equation

use the names of the chemicals involved to depict a chemical reaction. There are no chemical symbols or formulae in word equations. They provide basic understanding of what is happening in the reaction. For example, "Hydrochloric acid reacts with sodium hydroxide to form water and salt".

Chemical equations

Are more precise in representing chemical reactions they use chemical symbols and formulas involved in the reaction to show and identity the reactants and products

Balancing Chemical equations

In obeying the Law of Conservation of Mass, the chemical equations must be balanced and correct. A chemical equation is balanced if there is the same number of atoms on each side of the reaction.

Equations

can be balanced by inspection and a trial-and-error process, wherein coefficients before any of the chemical formulas are written until there is the same number of each atomon both sides of the equation

Coefficients

are whole numbers written in front of a symbol or chemical formula that represents the number of moles of the element or compound within the reaction.

Chemical reactions

Chemical reactions occur constantly around us, transforming substances into new ones and often showing visible changes like color shifts, temperature changes, or bubble formation

Reaction rates

measure how quickly these reactions happen, quantifying the speed of reactant-to-product conversion.

Rates

vary widely-from fast processes like combustion to slow ones like iron rusting. They significantly impact environmental processes, natural ecosystems, and human activities.

Temperature

measures the kinetic energy (motion energy) of a substance's particles; as temperature rises, particles move faster.

Higher temperature

make particles collide more often, speeding up reactions;

Lower temperature

reduce collisions, slowing them

Temperature

affects particle motion

Surface area

is the total area of a material's faces. Increasing it raises reaction rates by exposing more particles to interact

Concentration

refers to the amount of solute in a solution

Higher concentration

increases particle contact and collision frequency (per collision theory), accelerating reactions.

Effective collisions

cause chemical reactions and form products;

Ineffective collisions

do not result in reactions.

Catalyst

Substances that change reaction rates by lowering activation energy. Most speed up reactions and remain unaltered/unchanged from start to finish

Photosynthesis

which occurs in chloroplasts-converting carbon dioxide, water, and sunlight into glucose and oxygen.

Digestion

Chemical reactions break down complex nutrients into absorbable molecules, with enzymes (e.g., amylase for starch-to-glucose conversion) playing a key role. Reaction rate affects digestion efficiency and nutrient uptake; faster enzymatic reactions improve absorption.

Spoilage

Caused by microbial reactions (bacteria, yeast, molds). Microbial growth and metabolism depend on temperature, humidity, and oxygen-warmer conditions speed up spoilage.

Combustion

A rapid reaction of fuel with oxygen producing heat, light, CO2, and water. It's essential for energy production but contributes to air pollution and climate change.

Burning fossil fuels

releases sulfur/nitrogen oxides that react with water vapor to form acid rain.

Activation energy

The minimum energy reactant molecules need to start a chemical reaction and form products. It acts as an energy barrier-reactants must overcome it, similar to a ball needing energy to climb out of a valley. While reactants have kinetic energy from motion, additional energy is required to break old bonds and form new ones.

Liquid nitrogen

Laboratories use _______ (a cryogenic freezer) for cryopreservation-cooling samples to -196°C (77 K) stops biochemical reactions that cause cell death, preserving cells or tissues (Figure 8.4 illustrates this process).

Correct concentration

is essential for prescribed medicines-some work better at higher doses, while excess amounts can harm patients.

Wood and leather artifacts

are soaked in polyethylene glycol (a waxy substance) to strengthen them and restore flexibility.

Polyethylene glycol

A waxy substance

Coal

Grinding ___ into powder increases its surface area, accelerating combustion-power companies use this for more efficient reactions. Powders like fireworks and gunpowder also rely Won increased surface area for better reactivity.

Gases

Surface area affects fire spread: ____ have high surface area and spread easily (e.g., gasoline stations prohibit smoking to avoid explosions). Fire retardants (often powdnbmn ver-based, mixed into foams/gels) are used to control or stop fires.