PS1-2 Reactants/Products and Chemical/Physical

To help relieve pain during a dental visit, a dentist may give a patient nitrous oxide. Nitrous oxide is made in factories by carefully heating ammonium nitrate. At 170°C, ammonium nitrate breaks down and forms a mixture of nitrous oxide gas and water vapor. After the mixture is collected, the water vapor is separated from the nitrous oxide gas.

In this chemical reaction ammonium nitrate is a ________

• product

• reactant

People have used gunpowder as an explosive for hundreds of years. Gunpowder is a mixture of three different substances: potassium nitrate, charcoal, and sulfur. When these substances are burned together, they release a large amount of heat and gas. In the past, gunpowder was used in muskets and cannons, but today, it is mainly used in fireworks.

In this chemical reaction potassium nitrate is a ______

• reactant

• product

When the Statue of Liberty in New York City was built in the late 1800s, it was reddish-brown. Today, a green layer, called a patina, covers the statue's surface. This layer formed over time as copper in the statue combined with oxygen and other gases in the air to form the patina.

In this chemical reaction oxygen is a

• reactant

• product

If you visit a cave, you may notice icicle-shaped rocks called stalactites hanging from the cave's ceiling. Stalactites form when water that contains minerals drips from the cave's ceiling. The dripping water leaves behind deposits of limestone, which is made mostly of calcium carbonate (CaCO3). Calcium carbonate forms, along with carbon dioxide gas (CO2), when calcium bicarbonate (CaH2C2O6) in the water breaks down. The limestone deposits build up over thousands of years, eventually forming stalactites.

In the chemical reaction described in the passage, which of the following are products?Select all that apply.

• calcium carbonate (CaCO₃)

• carbon dioxide (CO₂)

• calcium bicarbonate (CaH₂C₂O₆)

Strawberry aldehyde (C12H14O3) is a chemical that helps give strawberries their smell. Many people enjoy this smell, so strawberry aldehyde is often added to perfumes and soaps. Factories can make this fragrant chemical by combining acetophenone (C8H8O) with ethyl chloroacetate (C4H7ClO2). This combination forms strawberry aldehyde and hydrochloric acid (HCl). Making fragrant chemicals like strawberry aldehyde in a factory is often less expensive than extracting the same chemicals from plants.

In the chemical reaction described in the passage, which of the following are reactants?Select all that apply.

• hydrochloric acid (HCl)

• strawberry aldehyde (C₁₂H₁₄O₃)

• acetophenone (C₈H₈O)

• ethyl chloroacetate (C₄H₇ClO₂)

What do these two changes have in common?

water evaporating from a puddle cooking a pancake

Select all that apply.

• Both are only physical changes

• Both are chemical changes

• Both are caused by heating

• Both are caused by cooling

What do these two changes have in common?

newly poured concrete becoming hard rust forming on a bicycle frame

Select all that apply.

• Both are only physical changes

• Both are chemical changes

• Both are caused by heating

• Both are caused by cooling

What do these two changes have in common?

breaking a piece of glass

water freezing into ice

Select all that apply.

• Both are only physical changes

• Both are chemical changes

• Both are caused by heating

• Both are caused by cooling

What do these two changes have in common?

firing a clay pot in a hot kiln

melting wax

Select all that apply.

• Both are only physical changes

• Both are chemical changes

• Both are caused by heating

• Both are caused by cooling

What do these two changes have in common?

cellular respiration

a piece of pizza rotting in a trashcan

Select all that apply.

• Both are only physical changes

• Both are chemical changes

• Both are caused by heating

• Both are caused by cooling