Matter - ARTI

Examine the illustrations below. Which does not represent a pure substance?

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Answer explanation

Pure substances are a classification of matter made up of all the same type of atoms, all the same molecules, or all the same bonded elements. Elements and compounds are both pure substances.

Chloe, Grace, and Julian are having a chemistry competition! They're trying to balance a tricky equation. Can you help them figure out the correct coefficients?

• 1,3,3

• 1,1,2

• 3,1,2

• 1,3,2

Answer explanation

The correct coefficients to balance the equation are 1, 3, and 2. This choice ensures that the equation is balanced and all elements have the same number of atoms on both sides.

Organize the two reactions into the right categories

Groups:

(a) Endothermic Reaction

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(b) Exothermic Reaction

• leaves surroundings feeling cold

• releases thermal energy

• fire is an example

• absorbs thermal energy

• an ice cube is an example

• energy can be released as heat or light

Answer explanation

Endothermic reactions absorb thermal energy thus makes objects cold. Exothermic is the opposite and releases thermal energy making object hot.

Jeffern, Luke, and Chalae', and Sari are having a friendly competition to see who can balance this chemical equation the fastest. Can you beat them to it? What are the coefficients that will balance this equation?

• 2,1,1

• 3,4,2

• 2,2,1

• 4,3,2

Answer explanation

The correct coefficients to balance the equation are 2, 2, and 1. This choice ensures that the number of atoms on both sides of the equation is equal.

After a fun science class about mixtures, Monte', Heysell, and Jordyn decided to put their knowledge to the test. They remembered that individual components of a solution retain their properties. Now, they are brainstorming different ways to separate mixtures. Can you help them out? Select ALL methods that could be used to separate different mixtures.

• filtration

• magnetism

• dissolving

• evaporation

Answer explanation

Filtration, magnetism, and evaporation can be used to separate different mixtures. These methods exploit the physical properties of the components to achieve separation.

Harriet is planning to go down an 8-m water slide.  Her weight is 50 N.  She knows that she has gravitational potential energy (GPE) at various points on the slide.  At each point, her GPE can be found by using an equation.  To investigate the relationship between potential energy and position, she uses the equation below to calculate her GPE at 8m, 6m, 4m, 2m, and 0m.

GPE = weight × height above ground

Groups:

(a) Independent Variable

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(b) Dependent Variable

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(c) Constant

• gravitational potential energy

• weight

• height above the ground

Answer explanation

Independent Variable - is what is being "changed" in an experiment.

Dependent Variable - what what is being "measured" in an experiment.

Constant Variable - what stays the "same" in an experiment.

Which 6 images best represent a physical change.

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Answer explanation

Physical Change - when matter is changed but NO new substance is created.