Topic 10 How to tell that a new substance has formed — what needs James (15)

Topic 10 · How to tell that a new substance has formed · Type 1 · tests MAT5-040

EasyMCQType 1 — a described mixing: which sign is this

A copper penny is dropped into a cup of clear liquid, and the liquid turns blue and stays blue. Which sign is this?

1. a) a gas is made
2. b) a color change that stays ← key
3. c) a new solid appears
4. d) warmer or colder by itself

Why it is this type: The liquid was clear, and the penny was copper-colored. The liquid turns blue, and the blue stays. That is the sign: a color change that stays.

Recommendation: Approve as the exemplar

Topic 10 · How to tell that a new substance has formed · Type 2 · tests MAT5-040

EasyMCQType 2 — which of four happenings is a sign (three are the taught near misses: drying, melting, boiling, a sun-warmed cup, a wet look, a color a substance already had)

Which of these is a sign that a new substance formed?

1. a) a puddle dries up in the sun
2. b) a cup fizzes when a powder meets a liquid ← key
3. c) snow melts in a warm room
4. d) a sheet of paper is cut in two

Why it is this type: Bubbles rush up where there were none before: a gas is made. Drying, melting and cutting keep the same substance. So the fizzing cup is the sign.

Recommendation: Approve as the exemplar

Topic 10 · How to tell that a new substance has formed · Type 3 · tests MAT5-040

MediumMCQType 3 — why bubbles count as a sign; which happening is a mix warming BY ITSELF; which test shows the bubbles are a new gas; the claim's correct reason (hard)

A cleaning tablet is dropped into a toilet bowl, and bubbles rush up with nothing heating the water. Why do the bubbles count as a sign?

1. a) A gas that was not there before is being made. ← key
2. b) The water is turning to gas as it warms.
3. c) Air trapped in the tablet is getting out.
4. d) Water always bubbles when something drops in.

Why it is this type: Nothing heats the water, so the bubbles are not water turning to gas. The dry tablet holds no bubbles, so they are not trapped air. So a gas that was not there before is being made: a sign.

Recommendation: Approve as the exemplar

Topic 10 · How to tell that a new substance has formed · Type 4 · tests MAT5-040

MediumtypedType 4 — the one word for what is being made when bubbles rush up with nothing heating the cup; the TWO signs in one scene (multi, hard)

Bubbles rush up in a cup where there were none before, and nothing is heating the cup. Type the one word for what is being made.

Accepted answers (typed): gas / a gas / the gas / gases / gass; wrong_fb for bubbles, air, foam, steam.

Why it is this type: Bubbles rush up where there were none before, with nothing heating the cup. So a gas that was not there before is being made. The one word is gas.

Recommendation: Approve as the exemplar

Topic 10 · How to tell that a new substance has formed · Type 5 · tests MAT5-041

EasyMCQType 5 — four things mixed into four containers, each with its happening: which mixing made a new substance

Four things are stirred into four cups of water. Which mixing made a new substance?

1. a) flour, which turns the water cloudy
2. b) rice, which sinks in the water
3. c) a powder, which fizzes in the water ← key
4. d) pebbles, which rattle in the water

Why it is this type: Fizzing means a gas is made: a sign. Flour, rice and pebbles show no sign, so each is still itself. So the fizzing powder made a new substance.

Recommendation: Approve as the exemplar

Topic 10 · How to tell that a new substance has formed · Type 6 · tests MAT5-041

MediumMCQType 6 — what the mixed thing is now / what the container holds / which sentence is true after a described mixing

Ground cinnamon is stirred into a bowl of applesauce and spreads through it with no sign. What is the cinnamon now?

1. a) cinnamon, in a mixture ← key
2. b) a brand-new substance
3. c) gone from the bowl
4. d) part of the applesauce

Why it is this type: No sign appeared. No sign means each substance is still itself. So the cinnamon is still cinnamon, spread through the applesauce, in a mixture.

Recommendation: Approve as the exemplar

Topic 10 · How to tell that a new substance has formed · Type 7 · tests MAT5-041

HardMCQType 7 — the claim's correct reason (the dissolving trap); which of two happenings in one scene is the sign; the one word for what a sign-free mixing leaves (typed)

Jude stirs powdered milk into water until it cannot be seen. He says a new substance formed because the powder disappeared. Jude is wrong. What is the correct reason?

1. a) The powder is still itself, spread through the water. ← key
2. b) The powder has turned into water as it spread.
3. c) The powder is gone for good from the glass.
4. d) The powder has become a gas and floated away.

Why it is this type: The powder dissolved: it spread through the water in pieces too small to see. A dissolved substance is still itself, and dissolving is not a sign. So no new substance formed. Hard because: a documented belief (SD-3 belief 2, the dissolving trap) judged by its correct reason.

Recommendation: Approve as the exemplar

Topic 10 · How to tell that a new substance has formed · Type 8 · tests MAT5-041

Hardmulti-selectType 8 — the TWO mixings of four that made a new substance

Four things are mixed into four cups of water. Select the TWO mixings that made a new substance.

1. a) flour, which spreads through and makes the water cloudy white
2. b) a powder, which fizzes and turns the water pink, and the pink stays ← key
3. c) a gray chip, which makes the cup hot by itself ← key
4. d) honey, which sinks and then spreads through

Why it is this type: Fizzing and a color change that stays are signs, and a cup hot by itself is a sign. Flour and honey spread through the water and show no sign. So the fizzing pink powder and the hot gray chip made a new substance.

Recommendation: Approve as the exemplar

Topic 10 · How to tell that a new substance has formed · Type 9 · tests MAT5-042

EasyMCQType 9 — a named change and a temperature that rises or falls: how does the change go now

Cookies are baking, and the oven is turned up hotter. How do the cookies turn brown now?

1. a) faster ← key
2. b) slower
3. c) at the same pace
4. d) not at all

Why it is this type: When the temperature rises, a change happens faster. The oven's temperature rose. So the cookies turn brown faster.

Recommendation: Approve as the exemplar

Topic 10 · How to tell that a new substance has formed · Type 10 · tests MAT5-042

MediumMCQType 10 — four places with their times: where did the change happen fastest / slowest

[pp_nails_table: four rows — the cold shed 11 days; the cool porch 8 days; the warm kitchen 4 days; the hot attic 2 days] Four wet iron nails are left in four places, and here is how many days passed before red-brown flakes showed on each. Where did the flakes show first?

1. a) the cold shed
2. b) the cool porch
3. c) the warm kitchen
4. d) the hot attic ← key

Why it is this type: The hot attic is the highest temperature of the four. When the temperature rises, a change happens faster. So the flakes showed first in the hot attic, after 2 days.

Recommendation: Approve as the exemplar

Topic 10 · How to tell that a new substance has formed · Type 11 · tests MAT5-042

HardtypedType 11 — the pace word produced from a temperature that rises or falls (typed, hard); the place that slows a new-substance change the most; the sentence true of BOTH kinds of change; one object drying and rusting at once

A wet iron bolt is moved from a cold garage to a warm shed. Type the one word for how the pace of its rusting changes.

Accepted answers (typed): faster / quicker / more quickly / speeds up; wrong_fb for slower, same, warmer, quick.

Why it is this type: When the temperature rises, a change happens faster. The warm shed is the higher temperature. The one word is faster. Hard because: the student produces the pace word from a temperature that rises.

Recommendation: Approve as the exemplar