Water and Chemistry 101

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elements

-made up of one kind of atom -make up the periodic table

the pH scale

0 to 14 0-6.9- acid 7.1-14 - base 7 - neutral

how many atoms and molecules does 2H2+02->2h2o

2 atoms 3 molecules

what percent of organisms are made up of chnops

97%

How does water help cells keep an even temperature despite temperature changes in the environment

Because of hydrogen bonds, water must gain or lose a relatively large amount of energy for its temperature to change. it tends to resist temperature changes

What six elements are most important in organisms

Carbon, hydrogen, oxygen, nitrogen, phosphorus, and sulfur

How are chemical reactions important in cells

Chemical reactions form new molecules needed for growth and repair and make energy available for cellular activity

What is the relationship between atoms and elements

Elements are made up of particles called atoms

Neutral

H+ = OH-

Distinguish among the various types of chemical bonds

Ionic bonds involve a transfer of electrons. Covalent bonds involve sharing of electrons. Polar covalent bonds is where the electrons are shared unequally. Hydrogen bonds form between a slightly positive hydrogen of one polar molecule and a slightly negative atom of another.

Why is pH important to living organisms

It helps to regulate a cell's chemical reactions

Describe the law of conservation of matter

It states that matter is neither created nor destroyed in chemical reactions

Why is water a good solvent

It's polar nature allows it to dissolve other polar substances as well as ionic compounds

What are the particles of an atom and how do they interact

Protons and neutrons form the atomic nucleus. electrons are present as a cloud around the nucleus. the number of protons and electrons are equal, so an atom has no charge

How does the polarity of water assist the movement of molecules

The polarity of water molecules allows them to dissolve many substances, facilitating their movement within and between cells. Also, the ability of water molecules to form hydrogen bonds helps stabilize large molecules such as proteins and nucleic acids.

A fire can be started by rubbing 2 sticks together until the wood ignites. What is this an example of

activation energy

What property of water allows it to stick to a dry surfaces

adhesion

How does capillary action occur

adhesion- water is attracted to molecules of another substance cohesion- water molecules attracted to each other defined as water moving up the vessels of plants

hydrogen bond

an attraction between a positive hydrogen atom in a molecule and a region of negative charges in another

cohesion

an attractive force between same substances

adhesion

an attractive force between unlike substances

If an atom or molecule gains or loses an electron, what does it become

an ion

What kinds of substances besides water can be involved in hydrogen bonding

any molecule that has a region of negative charge or a hydrogen with a slight positive charge can be involved in hydrogen bonding

isotopes

atoms of the same element that differ in the number of neutrons radioisotopes- unstable nuclei

hydrogen bonds

between a hydrogen (H+) atom and a region of (-) charge in another atom

ion

charged atom that is positive or negative

When a glass is filled to the brim with water, the water appears to bulge from the side of the glass due to what

cohesion

Explain why water forms large, round drops as they fall from a faucet with a slow leak

cohesion forces causes the water molecules in each drop to move as close as possible to one another making the drop round

Chemical reactions occur in living cells, what is this reaction not important to

creation of new elements

polar covalent

electrons are not shared equally

nonpolar covalent

electrons are shared equally

what does chemical bonding form

forms molecules or compounds between elements

When liquid water is heated, most of the energy that the water initially absorbs is used to break down what

hydrogen bonds between water molecules

Describe the surface tension of water

it is greater than other substances since hydrogen bonds resist breaking

Water is often called a universal solvent because it dissolves most substances that are important to living things. What does this suggest about the nature of those substances

it suggests that that the substances are most often polar molecules or ionic compounds

freezing

liquid water becomes ice, less dense than water, at 4 degrees Celsius hydrogen bonds expand

acids

more H+ than OH-

bases

more OH- than H+

Which type of bonding occurs when electrons are shared equally

nonpolar covalent

When water is boiled, what happens to its chemical composition

nothing

atomic number

number of protons

atomic mass

number of protons and neutrons

When does hydrogen bonding occur in water

occurs between separate water molecules

polar compound

one with an uneven distribution of positive and negative charges

What element is most abundant in the human body

oxygen

What type of bond in water

polar covalent bond

the subatomic particles making up an atom are

protons, neutrons, and electrons

Describe heat of vaporization of water

quantity of heat required to convert liquid water to gas example is sweating- evaporative cooling to prevent sweating

chemical equations

reaction yields products

Describe the high specific heat of water

resistant to changes in temperature, high boiling point, moderates temperature in organisms

When sodium chloride is dissolved in water, what are the sodium ions attracted to

sodium ions are attracted to oxygen atoms of water molecules

A dissolving substance

solute

activation energy

the energy needed to start a reaction

what do reactions involve

the making and breaking of chemical bonds

In a water molecule, which atom has a slightly negative charge and which one has a slightly positive charge

the oxygen has a slightly negative charge and the hydrogen atoms have a slightly positive charge

What does C6H12O6 not tell

the position of atoms

What is water known as

the universal solvent

ionic bonding

transfer of electrons

ionization of water

water dissociates into ions- H+ ions, OH- ions (hydr


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