24 Questions
What is the primary characteristic that distinguishes an element from a compound?
Its composition of atoms of two or more elements
Which of the following is an example of a physical change?
The melting of ice in water
What is the main difference between the properties of a gas and a solid?
The intermolecular forces between molecules
Which of the following is NOT a characteristic of a compound?
Can be separated by physical means
What is the result of hydrogen burning in air?
Formation of water
What is the primary difference between a mixture and a compound?
The ability to be separated by physical means
Which of the following is an example of a chemical change?
The burning of gasoline
What is the difference between mass and weight?
Mass is the quantity of matter, while weight is the force of gravity on an object
What is the SI unit of volume?
Cubic meter (m³)
What is the density of the piece of platinum metal?
21.5 g/cm³
What is the mass of the piece of platinum metal?
96.05 g
What is an example of an intensive property of a material?
Temperature
What is the main focus of the field of chemistry?
The study of matter and the changes it undergoes
What is a hypothesis in the scientific method?
A tentative explanation for a set of observations
What is a characteristic of a substance?
It has a definite composition and uniform properties
What is a heterogeneous mixture?
A combination of two or more substances with a non-uniform composition
What is an example of a law in chemistry?
Force = mass x acceleration
What is the definition of matter?
Anything that occupies space and has mass
What is the value of m in the equation d = m x V, given that d = 21.5 g/cm3 and V = 4.49 cm3?
96.5 g
What is the temperature in Celsius of 212°F?
100°C
What is the number of atoms in 12g of carbon, approximately?
6.022 x 10^23
What is the conversion of 1 lb in Newtons, approximately?
4.45 N
What is the mass of a single carbon atom in grams, approximately?
1.99 x 10^-23
What is the value of x in the equation F = 9/5 × C + 32, given that F = 172.9°F?
78.3°C
Study Notes
Physical Means of Separation
- Physical means can be used to separate a mixture into its pure components
- Examples of physical means include distillation and magnets
Elements
- An element is a substance that cannot be separated into simpler substances by chemical means
- 114 elements have been identified, with 82 occurring naturally on Earth and 32 created by scientists
- Examples of elements include gold, aluminum, lead, oxygen, and carbon
Compounds
- A compound is a substance composed of atoms of two or more elements chemically united in fixed proportions
- Compounds can only be separated into their pure components (elements) by chemical means
- Examples of compounds include water (H2O), glucose (C6H12O6), and ammonia (NH3)
The Three States of Matter
- The three states of matter are solid, liquid, and gas
- Physical state properties of the three states of matter:
- Solid: fixed volume and shape, particles are closely packed and have low kinetic energy
- Liquid: fixed volume, takes shape of container, particles are close together and have moderate kinetic energy
- Gas: variable volume, takes volume of container, particles are far apart and have high kinetic energy
Physical and Chemical Changes
- A physical change does not alter the composition or identity of a substance
- A chemical change alters the composition or identity of the substance(s) involved
Extensive and Intensive Properties
- An extensive property of a material depends on how much matter is being considered
- Examples of extensive properties include mass, length, and volume
- An intensive property of a material does not depend on how much matter is being considered
- Examples of intensive properties include density, temperature, and color
Matter
- Matter is anything that occupies space and has mass
- The SI unit of mass is the kilogram (kg)
- Weight is the force that gravity exerts on an object
International System of Units (SI)
- The SI derived unit for volume is the cubic meter (m3)
- 1 cm3 = (1 x 10-2 m)3 = 1 x 10-6 m3
- 1 dm3 = (1 x 10-1 m)3 = 1 x 10-3 m3
- 1 L = 1000 mL = 1000 cm3 = 1 dm3
Density
- The SI derived unit for density is kg/m3
- Density formula: mass density = volume (m d= V)
- Example problem: A piece of platinum metal with a density of 21.5 g/cm3 has a volume of 4.49 cm3. What is its mass?
Chemistry: A Science for the 21st Century
- Chemistry is the study of matter and the changes it undergoes
- Chemistry is important in various fields, including health and medicine, materials and technology, food and agriculture, and energy and the environment
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