Module 4 - Measurement Flashcards

week 4 (24 cards)

1
Q

What are the three basic parts of a quantity?

A

Magnitude, unit, and uncertainty.

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2
Q

How are measurements expressed?

A

Using magnitudes and units.

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3
Q

What does a magnitude imply?

A

It contains implicit information about uncertainty.

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4
Q

What are the four main SI base units?

A

Meter (m), kilogram (kg), second (s), and kelvin (K).

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5
Q

What are derived SI units?

A

Units formed by combining base units.

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6
Q

How is scientific notation structured?

A

As a significand and an exponent (order of magnitude).

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7
Q

What are prefixes used for in scientific notation?

A

To express orders of magnitude.

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8
Q

What are exact numbers?

A

Defined values with infinite significant figures.

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9
Q

What are uncertain numbers?

A

The result of measurements and have a degree of uncertainty.

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10
Q

What indicates the number of significant figures in a quantity?

A

The number of digits in the significand.

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11
Q

Are all non-zero digits significant?

A

Yes.

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12
Q

Are zeros in decimal notation significant?

A

They may be, depending on their placement.

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13
Q

What is the rounding rule for digits greater than 5?

A

Round up.

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14
Q

What is the rounding rule for digits less than 5?

A

Round down.

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15
Q

What is the rounding rule for exactly 5?

A

Round to the nearest even digit.

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16
Q

What is accuracy?

A

Closeness of a measurement to an accepted standard.

17
Q

What is precision?

A

How closely multiple measurements agree with one another.

18
Q

What is the atomic mass unit (amu) based on?

A

The mass of a hydrogen atom (1.0 amu).

19
Q

What is an amu?

A

A relative mass unit used to compare atomic masses.

20
Q

Why was hydrogen chosen for the amu?

A

It is the lightest element.

21
Q

What is a mole?

A

The number of hydrogen atoms in 1.0 g of hydrogen, 6.02 × 10^23 atoms.

22
Q

What is molar mass?

A

The mass of one mole of a substance, in g/mol.

23
Q

How are atomic masses in the Periodic Table related to molar mass?

A

They correspond directly in g/mol.

24
Q

How do you calculate the number of moles in a sample?

A

Divide the mass by the molar mass.