Chapter 4 CK-12 Questions

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

Which compound has the lowest ratio of nitrogen to oxygen?

N2O5

Democritus believed that all natural substances were made of _____.

atoms

What is all matter made of?

atoms

T or F Every molecule of carbon dioxide consists of 1 atom(s) of carbon and 2 atom(s) of oxygen.

true

T or F The law of definite proportions is only applicable when the elements which are reacting together form the same product.

true

T or F Democritus suggested that the complete universe is made up of minute particles which are indivisible.

true

T or F Protons have much more mass than electrons do.

true

T or F The ancient Greek philosophers spend their time by debate and discussion.

true

T or F 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

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

T or F Atoms are the smallest particles in the universe.

false

What word does the ancient greek word "atomos" roughly translate to?

indivisible

What law states that elements can combine with one another in different mass ratios?

law of multiple proportions

Will the composition of water vary depending on its source? (Yes or No)

no

What do all atoms of the same element have in common?

number of protons

A neutral atom has equal numbers of ______and electrons.

protons

_____ are attracted to negatively charged particles and repelled from positively charged particles.

protons

What is contained in the nucleus of an atom?

protons and neutrons

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

How many grams of carbon would be present in carbon monoxide that contains 2.66 grams of oxygen?

2

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 to 1

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

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 to 16

n glucose (C6H12O6), the simplified ratio of C atoms to H atoms is

1 to 2

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

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

2.56 g of hydrogen reacts completely with 20.32 g of oxygen to form X g of water. X = ___g

22.88

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.

3 to 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 to 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

33.38

A neutral atom has 37 electrons. How many protons does the atom have?

37

The molecular formula for ethane is C2H6. What is the carbon:hydrogen mass ratio for ethane?

4 to 1

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? ___ g

40.1

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?

44

Serotonin (C10H12N2O) is a neurotransmitter. The ratio of C atoms to N atoms is _____

5 to 1

In carbon monoxide, there is always 1.33 g of oxygen for every 1 g of carbon. How many grams of carbon are in a 16.03 g sample of carbon monoxide? ____ g carbon

6.88

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?

64

Magnesium (24.30 g) reacts with hydrogen chloride (X g) to produce hydrogen gas (2.04 g) and magnesium chloride (96.90 g). How much hydrogen chloride was used in the reaction? ______ g HCl

74.42

Atoms of carbon-14 have ____ neutrons.

8

A 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

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

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

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 scientist discovered the electron?

JJ Thomson

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

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.

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? (2 answers)

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.

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.

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

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

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