Questions and Answers
To estimate the measurement when the smallest mark is at the tenths place, to which decimal place should you report?
Zeros that are to the left of the first nonzero digit are always considered significant.
False
What is the length reported if the end of the object is estimated halfway between 4.5 cm and 4.6 cm?
4.55 cm
In significant figures, all nonzero numbers are counted as __________.
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How many significant figures are in the measurement 4.050 L?
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What is the standard notation of 1.28 × 10⁷ m?
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Match each measurement to its number of significant figures:
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Write the measurement 0.030 m in scientific notation.
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The coefficient in scientific notation must always be a whole number.
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What is the scientific notation for the number 72001?
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Exact numbers are those obtained by measuring items with a ruler.
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The diameter of a virus is written in scientific notation as _____ cm.
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Which of the following numbers is in correct scientific notation?
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Convert 2.01 × 10⁻⁴ to standard notation.
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Match the following powers of ten with their respective standard numbers:
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Measured numbers must indicate the _____ value reported by the measuring device.
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What unit is commonly used to express the density of a solid?
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Substances with lower densities contain particles that are closely packed together.
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Calculate the density of a solid that has a mass of 100 g and displaces 25 cm3 of water.
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The density of oil is ___ g/mL, which allows it to float on water.
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Match the following substances to their densities:
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How does the density of a bowling ball that weighs 9 lb and has a volume of 5,453 cc compare to that of water?
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The density of a gas is usually measured in grams per cubic centimeter (g/cm3).
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What is the density of a high-density lipoprotein (HDL) sample with a mass of 0.258 g and a volume of 0.215 mL?
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How many protons are in the nucleus of a zinc atom with a mass number of 65?
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Isotopes of the same element have different numbers of protons.
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What is the mass number of a zinc atom that has 37 neutrons?
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An atom with 14 protons and 20 neutrons has a mass number of _____
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Which atomic symbol represents an isotope of magnesium with 24 mass number?
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Match the isotopes with their respective neutrons:
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Identify the element represented by the atomic symbol with 8 protons.
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The atomic symbol includes information about the number of neutrons.
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What is the atomic number of a sodium (Na) atom?
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A neutron has a greater mass than a proton.
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How many protons are in a sulfur atom?
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The mass number of potassium is __________.
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Match the following elements with their atomic numbers:
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What charge do protons carry?
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An atom is electrically neutral if it has an equal number of protons and electrons.
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What is the formula to calculate the number of neutrons in an atom?
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Study Notes
Medication Administration
- Medication is administered to a patient every 4 hours.
Standard and Scientific Notation
- Scientific notation expresses large or small numbers compactly.
- Example of Standard Format to Scientific Notation:
- Diameter of the Earth: 12,800,000 m = 1.28 × 10⁷ m
- Mass of a human: 68 kg = 6.8 × 10¹ kg
- Diameter of a virus: 0.0000003 cm = 3 × 10⁻⁷ cm
- A scientific notation number consists of a coefficient (1-10) and a power of ten.
- Example conversions:
- 0.00378 = 3.78 × 10⁻³
- 52,000 = 5.2 × 10⁴
Writing Numbers in Scientific Notation
- Convert given numbers to scientific notation:
- 35000 = 3.5 × 10⁴
- 0.000000016 = 1.6 × 10⁻⁸
- 0.000008 = 8 × 10⁻⁶
- 72001 = 7.2 × 10⁴
- 632 = 6.32 × 10²
- 0.00253 = 2.53 × 10⁻³
- "12.36 x 10⁶ cm" is in correct scientific notation.
Converting Scientific Notation to Standard Number
- Process involves moving the decimal point based on the power of ten.
- Example Standard Number conversions:
- 2.01 × 10⁻⁴ = 0.000201
- 1.8 × 10⁵ = 180000
- 9.25 × 10⁻⁶ = 0.00000925
- 2.67 × 10⁻¹ = 2.67
- 2.67 × 10² = 267
Significant Figures
- Significant figures include all confident digits and the estimated last digit.
- Measurement reporting rules focus on the smallest marked place value on the measuring device.
- Example of reported measurements:
- 4.5 cm (smallest mark is tenths)
- 4.55 cm (estimated halfway)
- Significant figure examples:
- 0.030 m = 2 significant figures.
- 4.050 L = 4 significant figures.
- 0.0008 g = 1 significant figure.
- 2.80 m = 3 significant figures.
Exact Numbers
- Exact numbers result from counting or defined quantities.
Density
- Density describes how closely particles are packed:
- High density = close packing (e.g., metals).
- Low density = more spaced particles.
- Density measurements:
- Solids and liquids in g/cm³ or g/mL.
- Gases in g/L.
- Examples include oil density (0.8 g/mL) which allows it to float on water (1.00 g/mL).
Measuring Density of Solids
- Solid density can be calculated by water displacement.
- Example calculation:
- Density of a lead weight = mass (226 g) / volume (20.0 cm³).
- Density of osmium = mass (50.0 g) / volume (2.22 cm³).
- Density of high-density lipoprotein calculated from mass and volume.
Atomic Mass and Structure
- Mass of protons/neutrons is approximately 1 amu, electrons are negligible.
- Atomic number equals the number of protons in an atom.
- Elements defined by their atomic numbers (e.g., Hydrogen = 1, Carbon = 6).
Neutral Atoms
- An atom is neutral with equal numbers of protons and electrons.
- Example: A calcium atom (atomic number 20) has 20 protons and 20 electrons.
Mass Number and Neutrons
- Mass number equals the total of protons and neutrons.
- Neutron calculation: mass number - atomic number = number of neutrons.
- Example: Potassium (mass number 39, atomic number 19) has 20 neutrons.
Isotopes
- Isotopes are variants of the same element with different mass numbers differing by neutron count but maintaining proton equality.
- Carbon isotopes include 12C, 13C, and 14C.
- Allows for identifying the number of protons, neutrons, and electrons within each isotope.
Atomic Symbols
- Atomic symbols include mass number as the upper left and atomic number as the lower left.
- Example symbol for magnesium isotope: Mg-24.
Learning Checks
- Assess knowledge by asking about significant figures, mass numbers, and isotopes.
- Exploring relationships between atomic structure, including protons, neutrons, and electrons within different elements and isotopes.
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Description
Test your knowledge on standard and scientific notation through this quiz. You'll explore the conversion of large and small numbers into scientific notation, honing your skills in mathematical representation. This is an essential topic for understanding measurements in fields like science and engineering.
