Chapter 2 practice problems
Acid, Base or Neutral? 2:1 ratio of OH- to H+
basic
Acid, Base or Neutral? sodium hydroxide
basic
how many protons, neutrons, and electrons? atomic mass = 84 element Kr
36 protons 48 neutrons 36 electrons
how many protons, neutrons, and electrons? Element: Be Atomic mass =9
4 protons 5 neutrons 4 electrons
A _____________ contains a dissolved substance called a ______________.
A solution contains a dissolved substance called a solute.
A solution with a(n) __________ pH has a(n) ___________ number of H⁺ and OH⁻ ions.
A solution with a(n) neutral pH has a(n) equal number of H⁺ and OH⁻ ions.
When water molecules are combined, which of the following is the most likely orientation of oxygen and hydrogen atoms of different molecules? A. Oxygen atoms of one molecule attract hydrogen atoms of other molecules, so that each oxygen atom is opposite the two hydrogen atoms from nearby molecules. B. There is no pattern to the orientation of water molecules when they are added together. They randomly orient themselves. C. Hydrogen atoms of one molecule attract hydrogen atoms of other molecules, so that each hydrogen atom is opposite the hydrogen atoms from nearby molecules.
A. Oxygen atoms of one molecule attract hydrogen atoms of other molecules, so that each oxygen atom is opposite the two hydrogen atoms from nearby molecules.
The weak attractive forces that hold water molecules together are called? A. polar covalent bonds. B. hydrogen bonds C. non polar covalent bonds D. ionic bonds
B. hydrogen bonds
_________________ occur when two pairs of _________________ are shared between the outer shells of two atoms. Examples include the ______________________.
Double covalent bonds occur when two pairs of electrons are shared between the outer shells of two atoms. Examples include the bond between 2 oxygen atoms.
Due to the partial charges on atoms in a water molecule, _______________ in water molecules are attracted to oxygen atoms in other water molecules.
Due to the partial charges on atoms in a water molecule, hydrogen atoms in water molecules are attracted to oxygen atoms in other water molecules.
Due to water's _____________, it is capable of dissolving a great number of substances.
Due to water's polarity, it is capable of dissolving a great number of substances.
atomic mass = 72 what element is it? how many protons, neutrons, and electrons?
Ge 32 protons 40 neutrons 32 electrons
place the elements in order from smallest to largest in mass Be, Kr, H, Mg, As, Br, Na, K, Ga, Li
H Li Be Na Mg K Ga As Br Kr
atomic mass=4 what element it? how many protons, neutrons, and electrons?
He 2 protons 2 neutrons 2 electrons
_________________ occur when partially positive _________________ attract partially negative atoms nearby. Examples include the _____________________________________
Hydrogen bonds occur when partially positive hydrogen atoms attract partially negative atoms nearby. Examples include the attraction between two molecules of water.
In a mixture of salt water, ___________ is the solute, ___________ is the solvent, and ___________is the solution.
In a mixture of salt water, salt is the solute, water is the solvent, and salt water is the solution.
In both directions on the scale, between the whole number value, there is a difference of _________ times the concentration of hydrogen ions and hydroxide ions. A pH of 5 is 100 times more acidic than a pH of 7.
In both directions on the scale, between the whole number value, there is a difference of ten times the concentration of hydrogen ions and hydroxide ions. A pH of 5 is 100 times more acidic than a pH of 7.
_______________ occur when atoms are held together by an attraction between negatively and positively charged___________. Examples include ___________________
Ionic bonds occur when atoms are held together by an attraction between negatively and positively charged ions. Examples include NaCl and MgCl₂.
Isotopes are atoms of ______________ element(s) that differ in their number of ______________.
Isotopes are atoms of the same element(s) that differ in their number of neutrons.
Sea water, which has a pH of _______, has a higher concentration of _________ than urine, which has a pH of ______.
Sea water, which has a pH of 8, has a higher concentration of OH⁻ than urine, which has a pH of 6.
_______________occur when one pair of _____________ is shared between the outer shells of two atoms. Examples include the _______________________________
Single covalent bonds occur when one pair of electrons is shared between the outer shells of two atoms. Examples include the bond between 2 hydrogen atoms
Some isotopes of an atom are ____________, while others are _____________, or radioactive. Carbon ___________ is an example of an unstable isotope of carbon.
Some isotopes of an atom are stable, while others are unstable, or radioactive. Carbon 14 is an example of an unstable isotope of carbon.
The atomic number of all three of these isotopes is ____________, because all three have the same number of ____________ in the nucleus.
The atomic number of all three of these isotopes is 6, because all three have the same number of protons in the nucleus.
The attraction of electrons in the covalent bond between the hydrogen and oxygen atoms in a water molecule is ___________.
The attraction of electrons in the covalent bond between the hydrogen and oxygen atoms in a water molecule is unequal.
The element ______________ has three isotopes: one with an atomic mass of 12, one with an atomic mass of 13, and one with an atomic mass of 14.
The element carbon has three isotopes: one with an atomic mass of 12, one with an atomic mass of 13, and one with an atomic mass of 14.
The larger oxygen atom, with more protons, is more __________________ than the hydrogen atom and attracts the electron pair closer.
The larger oxygen atom, with more protons, is more electronegative than the hydrogen atom and attracts the electron pair closer.
The main difference between a stable atom and an unstable isotope is its _______________, and whether or not it is radioactive. Radioactive, or unstable, isotopes release energy as they decay. This energy may be relatively harmless, or harmful, as is the case with ___________________ and gamma radiation.
The main difference between a stable atom and an unstable isotope is its atomic mass, and whether or not it is radioactive. Radioactive, or unstable, isotopes release energy as they decay. This energy may be relatively harmless, or harmful, as is the case with beta particles and gamma radiation.
The pH scale ranges from __ to ____ and is used to indicate the ___________ of a solution.
The pH scale ranges from 0 to 14 and is used to indicate the alkalinity of a solution.
The result is that the sodium and chloride ions ________________ in water.
The result is that the sodium and chloride ions dissociate in water.
The unequal sharing of electrons in a covalent bond creates a(n) ______________________
The unequal sharing of electrons in a covalent bond creates a(n) polar covalent bond.
The weak bond formed between the hydrogen atom of one water molecule and the oxygen atom of another water molecule is called a(n) ______________ bond.
The weak bond formed between the hydrogen atom of one water molecule and the oxygen atom of another water molecule is called a(n) hydrogen bond.
There is _____________ times as much OH⁻ in household ammonia as there is in seawater.
There is one thousand times as much OH⁻ in household ammonia as there is in seawater.
What type of bond? 2 water molecules 2 strands of DNA
hydrogen bonds
Triple covalent bonds occur when three pairs of _____________ are shared between the outer shells of two atoms. Examples include the _____________________
Triple covalent bonds occur when three pairs of electrons are shared between the outer shells of two atoms. Examples include the bond between 2 nitrogen atoms
When salt is added to water, the ____________ poles of the water molecules are attracted to the _____________ sodium ions, and the ____________ poles of the water molecule are attracted to the __________________ chloride ions.
When salt is added to water, the negative poles of the water molecules are attracted to the positive sodium ions, and the positive poles of the water molecule are attracted to the negative chloride ions.
A polar covalent bond can best be described as?
a bond where electrons are unequally shared, resulting in more electrons orbiting certain atoms than others.
What is true about the structure of a water molecule?
a water molecule has one oxygen atom and two hydrogen atoms the bonds of a water molecule are polar
Acid, Base or Both? HCl is an example of a strong one
acid
Acid, Base or Both? Increases H+
acid
Acid, Base or Both? found in foods like lemon juice, vinegar, and coffee
acid
Acid, Base or Neutral? H+ concentration of 10^-5
acidic
Acid, Base or Neutral? pH of 3
acidic
Acid, Base or Neutral? tomatoes
acidic
Acid, Base or Both? NaOH is an example of a strong one
base
Acid, Base or Both? increase OH-
base
Acid, Base or Both? take up H+
base
Acid, Base or Both? commonly associated with milk of magnesia, or bicarbonate soda which decrease stomach acid
both
Acid, Base or Both? disassociate in water
both acid and base
Acid, Base or Both? strength can be measured by the pH scale
both acid and base
Compared to the polar covalent bonds that hold the oxygen and hydrogen atoms together within a molecule of water, the hydrogen bonds that hold multiple water molecules together are much stronger. true or false?
false Hydrogen bonds are weak attractive forces and are much weaker than polar covalent bonds.
Electrons possess a negative charge. So, within a molecule of water, if more electrons are orbiting the oxygen atom than the two hydrogen atoms, the oxygen atom will have a slightly more positive charge than the hydrogen atoms. true or false?
false If more electrons are orbiting the oxygen atom than the two hydrogen atoms, it will have a slightly more negative charge than the hydrogen atoms
What type of bond? NaCl MgCl2
ionic
Acid, Base or Neutral? pH of 7
neutral
Acid, Base or Neutral? pure water
neutral
What type of bond? H2 CH4
non polar covalent
What type of bond? H2O
polar covalent bond