Chemistry Chapter 4
Democritus proposed the theory of atomism.
True
Democritus stated that different atoms differ in magnitude.
True
Democritus suggested that the complete universe is made up of minute particles which are indivisible.
True
Electrons can be deflected by a magnetic field.
True
A reaction of heating calcium carbonate produces calcium oxide and carbon dioxide gas. Heat 10.0 g calcium carbonate until no more carbon dioxide gas is given off. The remaining material has a mass of 5.6 g. What mass of carbon dioxide gas was produced in the reaction? ___ g
4.4
A reaction between ammonia gas and chlorine gas produces ammonium chloride and nitrogen gas. A reaction of 17.0 g of ammonia with 26.6 g of chlorine gas gives off 3.50 g of nitrogen. What mass of ammonium chloride is formed in the reaction?
40.1g
The "clusters" of Democritus are like what kind of material that we know of today?
Compounds
Who was known as 'The Laughing Philosopher'?
Democritus
An atom can have 2.5 protons, as long as it also has 2.5 electrons.
False
A chemical compound is always found to be made up of the same elements combined together in the same fixed proportion by mass. This is known as the:
Law of definite proportions
_____ are attracted to negatively charged particles and repelled from positively charged particles.
Protons
What is the relationship between the masses of protons and electrons?
Protons are much more massive than electrons.
Before J.J. Thomson began gathering evidence about electrons in 1897, what did scientists know about atoms?
Scientists generally thought atoms were the smallest particles that could not be broken down any further.
According to Dalton, atoms cannot be ______.
Subdivided, Created, Destroyed
Which of the following best describes how Thomson concluded that electrons are present in all atoms.
The charge-to-mass ratio of electrons is always the same constant, no matter which substances are used in the cathode ray tube.
Which statement(s) about neutrons is/are TRUE?
They have the same mass as protons. The major clue to their existence was extra mass in atoms that protons and electrons could not account for.
Democritus believed that all natural substances were made of_____.
atoms
What is all matter made of?
atoms
A neutral atom has 37 electrons. How many protons does the atom have?
exactly 37 protons
A neutral atom has equal numbers of ______ and electrons.
protons
What is contained in the nucleus of an atom?
protons and neutrons
The proportion of the mass of one element to that of another element is a mass _____.
ratio
How does the mass of the neutron compare to the mass of the proton?
slightly greater
Which statements are TRUE about protons.
they have a mass over 1800 times greater than the mass of an electron. they have a positive charge.
According to the law of conservation of mass, if an atom of element A has a mass of 2 units, while an atom of element B has a mass of 5 units, what would be the mass of the compound A3B2?
16 units
The mass ratio of H to O in water (H2O) is 1:8. What is the mass ratio of H to O in hydrogen peroxide (H2O2)?
1:16
In glucose (C6H12O6), the simplified ratio of C atoms to H atoms is
1:2
______ are negatively charged, and are one of the types of particle which make up atoms.
Electrons
Dalton showed that matter always combined in fixed ratios based on mass or based on volume in the case of gases.
True
Dalton's atomic theory could not explain the law of gaseous volumes.
True
Dalton's atomic theory states that chemical reactions involve only the combination, separation, or rearrangement of atoms.
True
Democritus believed that atoms were always in motion.
True
Every molecule of carbon dioxide consists of 1 atom(s) of carbon and 2 atom(s) of oxygen.
True
Lavoisier discovered the principle of conservation of mass in chemical reactions.
True
Mass is always conserved in chemical reactions.
True
The Greek and Roman philosophers studied nature by discussed issues.
True
The ancient Greek philosophers spend their time by debate and discussion.
True
The idea of the atom was the major contribution of Democritus made to the thinking of his day.
True
The law of definite proportions is only applicable when the elements which are reacting together form the same product.
True
The law of multiple proportions states that whenever the same two elements form more than one compound, the different masses of one element combine with the same mass of the other element in the ratio of small whole numbers.
True
Whenever the same two elements form more than one compound, the different masses of one element that combine with the same mass of the other element are in the ratio of small whole numbers.
True
When did John Dalton start teaching school?
Twelve years old
The characteristics of atoms according to Democritus are _____.
Unchangeable, indestructible, always existed
In what general type of reaction are atoms combined, separated, or rearranged?
chemical
What law states that elements can combine with one another in different mass ratios?
law of multiple proportions
Atoms of different elements can combine in simple _____ number ratios to form chemical compounds.
whole
In carbon dioxide, there is always 2.66 g of oxygen for every 1 g of carbon. How many grams of oxygen are in a 25.62 gram sample of carbon dioxide?
18.62 g
How many valence electrons does beryllium have?
2
Atoms of carbon-14 have ____ neutrons.
8
Which statement best describes how protons were discovered?
A cathode ray tube revealed a ray of positive particles traveling in the opposite direction of negative electrons.
Who discovered the existence of the neutron?
Chadwick
At the time protons were discovered, it was apparent that they existed in a central nucleus.
False
Neutrons have neither charge nor mass
False
Nothing was known about atoms before electrons were discovered.
False
The neutron is located in the ______ of the atom.
Nucleus
Protons have much more mass than electrons do.
True
The number of protons and electrons in a neutral atom must be equal.
True
Which statement(s) about electrons is/are TRUE?
When they were first discovered, they were named "corpuscles." They have a negative charge. They have a tiny but significant mass.
What happens when an electron is removed from an atom?
a positive charge remains
The mass of a neutron is close to the mass of
a proton
What source supplied the electrons in J.J. Thomson's cathode ray tube experiment?
a simple electric current allowed electrons to flow through the tube
Water is 11.19% hydrogen and 88.81% oxygen by mass. Lake Superior contains about 1.2×1016 kg of water. What mass of hydrogen is contained in Lake Superior?
1.3 x 10^15 kg
A reaction of heating potassium permanganate produces potassium manganate, manganese dioxide and oxygen gas. Heat 15.8 g potassium permanganate until no more oxygen gas is given off. The remaining material has a mass of 14.2 g. What mass of oxygen gas was produced in the reaction? ___ g
1.6
In the compound nickel(II) sulfide, there is always 58.7 g of nickel for every 32.1 g of sulfur. What is the simplified ratio of nickel to sulfur?
1.83 to 1
A reaction of 12.640 g of copper oxide with 0.316 g hydrogen produces 2.844 g of water and X g of copper. X = ___ g
10.112
When heated, calcium hydroxide and ammonium chloride react to produce ammonia gas, water vapor, and solid calcium chloride. Suppose 5.00g of calcium hydroxide and 10.00g of ammonium chloride are mixed in a test tube and heated until no more ammonia is given off. The remaining material in the test tube has a mass of 1.27 g. What is the total mass of ammonia and water vapor produced? ___ g
13.73
In one compound of lead and sulfur, there are 6.46 g of lead for every gram of sulfur. In another, there are 3.23 g of lead for every gram of sulfur. What is the simple whole number ratio for the masses of lead that can make compounds with sulfur? (Write your answer ratio format. e.g: 5:2)
2 : 1
How many grams of carbon would be present in carbon monoxide that contains 2.66 grams of oxygen?
2 g
In the compound CH4, what is the carbon:hydrogen mass ratio?
3 : 1
There are two compounds of gold and chlorine. In one compound, there is 15.39 g of gold for every 2.77 g of chlorine. In the other compound, there is 7.74 g of gold for every 4.18 g of chlorine.Find the ratio of masses of gold in the two compounds. (Give in" x : y" format)
3 : 1
Two compounds of phosphorus and fluorine have the following mass ratios.Compound 1: 10.14 g fluorine for every 3.38 g phosphorusCompound 2: 8.42 g fluorine for every 4.21 g phosphorusFind the whole number ratio of masses of fluorine in compound 1 to compound 2.
3 : 2
A reaction of 22.85 g of sodium hydroxide with 20.82 g of hydrogen chloride produces 10.29 g of water and X g of sodium chloride. X = ___ g
33.38g
The molecular formula for ethane is C2H6. What is the carbon:hydrogen mass ratio for ethane?
4 : 1
Calcium carbonate, CaCO3, decomposes when heated to calcium oxide (CaO) and carbon dioxide (CO2). If 100 g of calcium carbonate is allowed to decompose, 56 g of calcium oxide is produced. What mass of carbon dioxide is produced by the decomposition? _____ g
44
A compound has 15.39 g of gold for every 2.77 g of chlorine. Simplified, there is ____ g of gold for every 1 g of chlorine. (Round to two decimal places)
5.56
Serotonin (C10H12N2O) is a neurotransmitter. The ratio of C atoms to N atoms is _____
5:1
The percent by mass of sodium in table salt (NaCl) is 39.34 %. What is the percent by mass of chlorine?
60.66%
In carbon dioxide, how many grams of oxygen would there be if there are 24 grams of carbon?
64g
Which statement(s) is/are FALSE?
All atoms are about the same size. Protons and neutrons repel each other and position themselves far apart inside the atom.
Which of the following statements is true about the atoms of any element?
All the atoms of a given element are identical in that they have the same number of protons.
Who was the most influential philosopher when it came to the subject of the composition of the natural world?
Aristotle
According to Democritus, which of these existed in reality?
Atoms and Void
Which of the following is/are not true about Dalton's theory of atoms?
Atoms can be subdivided into smaller particles
During a chemical reaction, the law of _______ _______ states that the total mass of the products must be equal to the total mass of the reactant.
Conservation of mass
A given chemical compound always contains the same elements in the exact same proportions by mass is the law of _____.
Definite proportions
_____ introduced the idea of the atoms as basic building block of matter.
Democritus
A chemical compound is always found to be made up of the same elements combined together in different proportions by mass.
False
According to Democritus, atoms are solid particles which are destructible.
False
An extension of Democritus theory states that there were different varieties of atomos with same shapes, sizes and masses.
False
Greek philosophers accepted most of the discoveries on the basis of experiments they performed.
False
In a given type of chemical substance, the elements never combine in the same proportions by mass.
False
In carbon dioxide, 12 grams of carbon combines with 16 grams of oxygen.
False
Matter is not conserved in chemical reactions.
False
Science and experimentation were active pursuits in ancient Greece.
False
The theory of Democritus and Leucippus held that everything is composed of 'atoms', which are geometrically indivisible.
False
Atoms are the smallest particles in the universe.
False, subatomic particles are
The mass ratio of hydrogen to oxygen in water (formula H2O) is 0.126 g hydrogen for every 1 g of oxygen. In another compound of hydrogen and oxygen called hydrogen peroxide, the mass ratio of hydrogen to oxygen is 0.063 g hydrogen for every 1 g of oxygen. What is a possible formula of hydrogen peroxide?
H2O2
Atoms, according to Democritus, always existed and are unchangeable and indestructible.
True
What is the health danger of breathing carbon monoxide?
It blocks oxygen from binding to hemoglobin.
Which of the following scientists discovered the electron?
J.J. Thomson
Who proposed the world's first atomic theory model and stated that all matter is made of atoms?
John Dalton
To propose his atomic theory, Dalton used:
Law of definite proportions, law of multiple proportions, law of conservation of mass
When one or more substances undergo a chemical reaction, the:
Mass of the reactant decreases and the mass of the product increases but the total mass remains the same.
Which compound of nitrogen and oxygen has the highest ratio of nitrogen to oxygen?
N2O
Which compound has the lowest ratio of nitrogen to oxygen?
N2O5
Did Dalton believe that atoms could be created or destroyed?
No
Will the composition of water vary depending on its source?
No
What do all atoms of the same element have in common?
Number of protons
According to Dalton's atomic theory, during a chemical reaction, there is _____ of atoms.
Rearrangement
Which of the following was/were used by the Greek philosophers in order to understand the world?
Reason
When combined, iodine and tin were found to produce two different molecules. Both contained the same mass of tin, but one had twice as much iodine. The molecular formula for one of the molecules is SnI2 , what is the formula for the other molecule?
SnI or SnI4
What evidence from the cathode ray tube experiment support the claim that electrons have a negative charge?
The cathode ray bent away from a negatively charged plate. The cathode ray bent toward a positively charged plate.
Identify the law that explains the following observation: Nitrogen dioxide can be formed by reacting 14 grams of nitrogen with 32 grams of oxygen.
The law of definite proportions
According to Dalton, all atoms of a given element are identical in mass and other properties.
True
According to Democritus, changes occur if atoms in an object are recombined or reconnected in different ways.
True
Ancient Greek philosophers had many ideas about the natural world and how it worked.
True
One piece of evidence for the Dalton's atomic theory is the observation that
a compound always has the same proportions of different elements
According to the atomists, the entire physical world was made of:
atoms and void
According to Dalton's atomic theory
atoms cannot be subdivided, created, or destroyed.
For any chemical process in an isolated system in which all reactants are converted to products, the original mass of reactants must be _____ the final mass of products.
equal to
In any chemical reaction or physical change, the mass of the products is ____ the mass of the reactants.
equal to
According to Aristotle, how long could one divide a grain of sand?
indefinitely
What word does the ancient greek word "atomos" roughly translate to?
indivisible
The radius of an atom is closest in size to a _________ .
nanometer
