Matter
Which state of matter has a definite shape and definite volume?
Solid
Is melting a physical or chemical change?
Physical change
What is the definition of density?
How tightly packed particles are. or The mass of a substance per unit volume.
What is a pure substance made of only one type of atom called?
Element
Is saltwater a homogeneous or heterogeneous mixture?
Homogeneous mixture (solution).
In which state of matter do particles move freely and take the shape of their container but have a definite volume?
liquid
Name two signs of a chemical change.
Color change, bubbling, heat/light emission, sound production.
If an object has a mass of 60g and a volume of 30cm³, what is its density?
2 g/cm³
What is a substance made of two or more elements chemically combined?
Compound
What type of mixture is muddy water where particles eventually settle?
Suspension.
What is the main difference between gas and plasma?
Plasma consists of charged (ionized) particles, while gas particles are neutral.
What is the difference between a physical and chemical property?
Physical properties can be observed without changing the substance (e.g., color, density), while chemical properties describe how a substance reacts (e.g., flammability).
A liquid has a density of 0.9 g/mL. Will it float or sink in water (1 g/mL)?
Float because it is less dense.
Is air a compound or a mixture?
Mixture (homogeneous).
Which type of mixture scatters light but does not settle over time?
Colloid
Describe the particle movement in a solid, liquid, and gas.
Solid: Tightly packed, vibrating. Liquid: Close together but can flow. Gas: Moving freely, far apart.
Identify two physical and two chemical properties of iron.
Physical: Malleability, density. Chemical: Rusting (oxidation), reactivity with acids.
Which layer is at the bottom in a density column: Oil (0.8 g/mL), Water (1.0 g/mL), Honey (1.4 g/mL)?
Honey (most dense)
Identify the following from an image: NaCl, Fe, H₂O. (Provide an image with examples.)
NaCl - Compound, Fe - Element, H₂O - Compound.
Identify the type of mixture from an image (Provide an image showing a colloid, solution, and suspension).
Colloid (e.g., milk), Solution (e.g., saltwater), Suspension (e.g., muddy water).
Why does plasma conduct electricity, but gases do not?
Plasma has free-moving charged particles (ions and electrons), while gases are electrically neutral.
If a substance burns and releases energy in the form of heat and light, is it a physical or chemical change? Explain why.
Chemical change, because a new substance is formed, and energy is released.
A rock is placed in a graduated cylinder. The water level rises from 40mL to 55mL. The mass of the rock is 30g. What is the density of the rock?
Density = Mass ÷ Volume = 30g ÷ (55mL - 40mL) = 2 g/mL
What is the key difference between a compound and a mixture?
A compound has 2 or more different elements chemically bonded, while a mixture consists of physically combined substances that can be separated.
What is the difference between a colloid and a solution?
A solution is completely dissolved at a molecular level, while a colloid has small particles that remain dispersed but do not settle.