Diversity of matter

A student has three unlabeled bottles containing powdered sugar, salt, and baking soda. Which scientific method would be most effective for identifying each substance?

• Dissolving each in water and testing the electrical conductivity

• Observing their crystal shapes under a microscope

• Testing their pH with universal indicator paper

• Burning each powder to observe the flame color

In an experiment, a student found that substance X conducts electricity when dissolved in water but not in solid form. Substance X is most likely:

• A covalent compound

• An ionic compound

• A metallic element

• A noble gas

When magnesium ribbon burns in air, it produces a white ash that turns red litmus paper blue. This indicates that the ash is:

• Acidic

• Basic

• Neutral

• Salty

A student designed a water filtration system using layers of gravel, sand, and activated charcoal. This system is most effective at removing:

• Dissolved salts and minerals

• Bacterial contaminants

• Suspended particles and some chemicals

• All types of water pollutants completely

In investigating metal reactivity, a student placed iron nails in copper sulfate solution and observed that the nails turned brown. This demonstrates:

• Iron is more reactive than copper

• Copper is more reactive than iron

• Iron and copper have equal reactivity

• No reaction occurred between them

Which property makes aluminum suitable for manufacturing aircraft bodies?

• High density and magnetic properties

• Low melting point and electrical conductivity

• Light weight and resistance to corrosion

• High cost and shiny appearance

A student noticed that an ice cube floats in water while a piece of iron sinks. This is because:

• Ice has lower density than water

• Water exerts upward pressure on ice only

• Iron has lower mass than ice

• Ice contains air bubbles that make it float

In a chromatography experiment to separate ink components, the substance that moves farthest up the paper is the:

• Least soluble component

• Most soluble component

• Heaviest component

• Darkest colored component

A farmer needs to adjust soil pH from acidic to neutral. The most appropriate substance to use would be:

• Sulfuric acid

• Calcium hydroxide

• Sodium chloride

• Ammonium nitrate

Which specialized cell adaptation makes root hair cells efficient at water absorption?

• Chloroplasts for photosynthesis

• Large surface area and thin walls

• Thick waxy cuticle

• Ability to perform active transport only