What Burns? What Melts?

What happens to chocolate when it absorbs enough thermal energy?

• It burns into ash

• It melts into a liquid

• It evaporates into gas

• It becomes solid

Tags

NGSS.MS-PS1-4

NGSS.MS-PS3-4

What happens to the molecules in chocolate as it melts?

• They disappear into the air

• They gain energy and start moving around more freely

• They react with oxygen

• They freeze together

Tags

NGSS.MS-PS1-4

NGSS.MS-PS3-4

What remains after wood finishes burning?

• Ash

• Liquid wood

• Charcoal gas

• Frozen wood

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-4

NGSS.MS-PS1-5

What is the temperature at which wood begins to break down and react with oxygen?

• 100°C (212°F)

• 150°C (302°F)

• 200°C (392°F)

• 50°C (122°F)

Tags

NGSS.MS-PS1-2

Which phase change occurs when chocolate absorbs enough heat?

• Gas to liquid

• Solid to gas

• Solid to liquid

• Liquid to gas

Tags

NGSS.MS-PS1-4

Why doesn’t wood melt when exposed to heat?

• Its melting point is lower than its flash point

• Its flash point is lower than its melting point

• Wood is heatproof

• Wood cannot absorb heat

Tags

NGSS.MS-PS1-4

What is combustion?

• A phase change from solid to liquid

• A chemical reaction with oxygen at high temperatures

• A cooling process

• A physical reaction

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

What happens to some of the molecules in wood during combustion?

• They react with nitrogen

• They turn into liquid

• They change into gas and escape into the air

• They freeze into crystals

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-4

NGSS.MS-PS1-5

What happens when you remove heat from melted chocolate?

• It reacts with oxygen

• It becomes gas

• It turns back into a solid

• It catches fire

Tags

NGSS.MS-PS1-4

1. Why does fire eventually go out if no new wood is added?

• 1. The fire absorbs too much heat

• 1. The combustion reaction runs out of fuel or oxygen

• 1. The fire becomes cold

• 1. The molecules freeze