Chapter 6 Flashcards

1
Q

The process of breaking the chemical bonds which hold the different atoms together in a compound is called __________.

A

decomposition

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2
Q

We call the mass ratio for each element present in a compound the _____ ________.

A

percent composition

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3
Q

A ________ ______ is the sum of the atomic masses of all the atoms represented in the chemical formula of a substance.

A

formula mass

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4
Q

The term _____ is a Greek term used to describe a heap or pile.

A

mole

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5
Q

The term _______ is the dimunitive form of a mole meaning the smallest portion of the heap or pile.

A

molecule

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6
Q

Chemists now use the value of a ____ like a baker uses the value of a dozen.

A

mole

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7
Q

Avogadro’s number of particles for any pure substance is equal to it’s ___ ____ ___ ____ rather than amu.

A

formula mass in grams

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8
Q

Since Avogadro’s number of particles for any substance is numerically equal to the formula mass in grams, the formula mass is often called the ___ ___ of a substance.

A

molar mass

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9
Q

____ ____ = the mass of 1 mole of a given substance.

A

molar mass

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10
Q

The molar mass of an element is numerically equal to the _____ _____ of that element.

A

atomic mass

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11
Q

The molar mass is used as a ______ ______ to calculate the number of moles found in a given gram mass of a substance or vice versa.

A

conversion factor

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12
Q

The ____ of ____ of _____ simply states that when making a chemical substance with exactly the right amount of ingredients, the resulting total product mass is exactly the same as the total starting mass. In other words, during a normal chemical reaction, mass cannot be created nor destroyed.

A

The law of conservation of mass

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13
Q

The _____ _____ is simply a description of the overall chemical reaction using the molecular or ionic formulas to represent the starting material(s) and the product(s).

A

chemical equation

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14
Q

The ingredients, which we call _____, are listed on the left side of the equation.

A

reactants

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15
Q

The final results or ______ of the reaction are listed on the right side of the equation.

A

products

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16
Q

Reactants are also called _____ _____.

A

chemical reagents

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17
Q

The ______ is a whole number used to describe the exact number of molecules or atoms that are needed to participate in an exact reaction.

A

coefficient

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18
Q

What is the subscript for gas?

A

(g)

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19
Q

What is the subscript for liquid?

A

(l)

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20
Q

What is the subscript for solid?

A

(s)

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21
Q

What is the subscript for aqueous solution (dissolved in water)?

A

(aq)

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22
Q

Before a chemical equation is actually useful, it must be _______.

A

balanced

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23
Q

When a chemical equation is balanced the ____ and ____ of atoms found on the left side will exactly match the number and types of atoms found on the right side.

A

number and types

24
Q

Only the _______ can be changed to balance an equation.

A

coefficient

25
Q

The word, ________ is a German term that means “element balance”.

A

stoichiometry

26
Q

______ ______ are done on paper assuming that the reaction will go to completion with no loss of either products or reactants.

A

Theoretical calculations

27
Q

The amount of product in theoretical calculations are called _____ _____.

A

theoretical yield

28
Q

After performing the chemical reaction and isolating the product, the actual weighed amount of product is called the _____ ______.

A

actual yield

29
Q

How close a chemist comes to isolating the theoretical amount of product from an actual experiment is called the ______ ______.

A

percent yield

30
Q

What is the calculation to find the percent yield?

A

actual experimental mass / calculated theoretical mass x 100

31
Q

The problem with knowing the number of atoms or molecules in a given sample of a pure substance is______________________________________.

A

the particles that make up the substance are too small and way too numerous to count.

32
Q

Elements in a given compound are always found in definite _______ or _______.

A

ratio or proportion

33
Q

What is the ratio of C atoms to O atoms in carbon dioxide?

A

1 carbon atom for every 2 oxygen atoms; 1:2 ratio

34
Q

How does one mix atoms in a proper ratio without counting them?

A

by weighing them

35
Q

Water has a fixed ratio by ____ of O atoms and H atoms.

A

mass

36
Q

TRUE or FALSE:

Pure water in Argentina has the same mass ratio of H and O as water in the US.

A

true

37
Q

TRUE or FALSE:

It is possible that 2 different compounds happen to have the same percent composition of elements.

A

true

38
Q

If an oxygen atom weighs 16.00amu and a hydrogen atom weighs 1.01amu, what is the total mass of a water molecule in amu?

A

18.02amu (sum of all atoms)

39
Q

What 2 pieces of information or data are required to count particles by weighing?

A

the average mass of each item present and the total mass of all items

40
Q

The molar mass and the ______ mass are numerically the same value.

A

formula

41
Q

If the units for the formula mass are amu, what are the units of the molar mass?

A

grams/mole

42
Q

TRUE or FALSE:

The molar mass is used to calculate the actual number of particles in a certain mass.

A

false - this would give the moles of particle

43
Q

What conversion factor is needed to convert from grams of a substance to moles of the substance?

A

molar mass

44
Q

If you are given grams of a substance and are asked to determine the number of atoms or molecules of that substance, what value must be calculated first?

A

moles

45
Q

TRUE or FALSE:
During a normal chemical reaction the mass of the products and any left over material always equal the mass of the starting materials.

A

true

46
Q

What is drawn between the reactants and products?

A

an arrow

47
Q

The plus sign in a chemical equation is equivalent to the word, ______.

A

and

48
Q

Products of a chemical reaction are listed on the _____ side of the equation.

A

right

49
Q

The coefficient is used to show the ____ ____ of reactants or product molecules required for or produced by the reaction.

A

actual number

50
Q
TRUE or FALSE:
If sulfur (S) is found in one of the product molecules it must also be present in one of the reactants.
A

true

51
Q

When balancing a chemical equation, only the ______ values can be altered.

A

coefficient

52
Q

Changing the subscripts of the formulas will change the ________ of the substance.

A

identity

53
Q
TRUE or FALSE:
If carbon (C) is found in all of the reactants, it must also be present in all of the products.
A

false

54
Q

Balancing a chemical reaction gives us the correct ______ ______ of reactants and products.

A

proper ratios

55
Q

TRUE or FALSE:

The actual yield can be calculated using stoichiometry and a balanced chemical equation

A

false