Exam question 2 · Molecules: when atoms join up

Identify the principal distinction between a mixture and a compound.

Mova's choice: option 3 · The right answer: option 3 · right ✓ · Who acts: you · What happens: identify · To what, where: principal distinction

This is exam question 2 of lesson 3 «Molecules: when atoms join up» of the chemistry course of Mova's primary school, asked in stiff, formal language. The page gives the question's syntax tree — a dependency tree in the style of Universal Dependencies — and its pragmatics clause by clause, then the 4 options as the student saw them, each with its tree and pragmatics. Every text is parsed by Mova itself. How the student answered it, with the score of every option and why: the test at school.

The question

The words, one row each (CoNLL-U)

#	word	lemma	UPOS	features	head	relation
1	Identify	identify	VERB	Mood=Imp VerbForm=Fin	root	root
2	the	the	DET	Definite=Def PronType=Art	4 distinction	det
3	principal	principal	ADJ	Degree=Pos	4 distinction	amod
4	distinction	distinction	NOUN	Number=Sing	1 Identify	obj
5	between	between	ADP	_	7 mixture	case
6	a	a	DET	Definite=Ind PronType=Art	7 mixture	det
7	mixture	mixture	NOUN	Number=Sing	4 distinction	nmod
8	and	and	CCONJ	_	10 compound	cc
9	a	a	DET	Definite=Ind PronType=Art	10 compound	det
10	compound	compound	NOUN	Number=Sing	7 mixture	conj
11	.	.	PUNCT	_	1 Identify	punct

#	verb	tense, mood	who	what, whom	to whom	where	when	other	roles by
1	identify	imperative	you not said here	the principal distinction				between a mixture and a compound	vn characterize-29.2-1-1 «NP V NP S_ING»: agent=Agent distinction=Theme

One row per clause the reader finds. «not said here»: a role filled from the clause above. «roles by»: a VerbNet class and frame when one fits the verb, else the reader's rules on the tree.

The options

Option 1

A mixture contains a single element only, whereas a compound contains a great many elements

The tree, 15 words

The words, one row each (CoNLL-U)

#	word	lemma	UPOS	features	head	relation
1	A	a	DET	Definite=Ind PronType=Art	2 mixture	det
2	mixture	mixture	NOUN	Number=Sing	3 contains	nsubj
3	contains	contain	VERB	Mood=Ind Number=Sing Person=3 Tense=Pres VerbForm=Fin	root	root
4	a	a	DET	Definite=Ind PronType=Art	6 element	det
5	single	single	ADJ	Degree=Pos	6 element	amod
6	element	element	NOUN	Number=Sing	3 contains	obj
7	only	only	ADV	_	6 element	advmod
8	,	,	PUNCT	_	12 contains	punct
9	whereas	whereas	SCONJ	_	12 contains	mark
10	a	a	DET	Definite=Ind PronType=Art	11 compound	det
11	compound	compound	NOUN	Number=Sing	12 contains	nsubj
12	contains	contain	VERB	Mood=Ind Number=Sing Person=3 Tense=Pres VerbForm=Fin	3 contains	conj
13	a	a	DET	Definite=Ind PronType=Art	16 elements	det
14	great	great	ADJ	Degree=Pos	16 elements	amod
15	many	many	ADJ	Degree=Pos	16 elements	amod
16	elements	element	NOUN	Number=Plur	12 contains	obj

#	verb	tense, mood	who	what, whom	to whom	where	when	other	roles by
1	contain	present	a mixture	a single element					vn comprise-107.2-2 «NP V NP»: agent=Pivot element=Theme
2	contain	present	a compound	a great many elements					vn comprise-107.2-2 «NP V NP»: agent=Pivot element=Theme

Option 2

A compound is invariably liquid, whereas a mixture is invariably solid

The words, one row each (CoNLL-U)

#	word	lemma	UPOS	features	head	relation
1	A	a	DET	Definite=Ind PronType=Art	2 compound	det
2	compound	compound	NOUN	Number=Sing	5 liquid	nsubj
3	is	be	AUX	Mood=Ind Number=Sing Person=3 Tense=Pres VerbForm=Fin	5 liquid	cop
4	invariably	invariably	ADV	_	5 liquid	advmod
5	liquid	liquid	ADJ	Degree=Pos	root	root
6	,	,	PUNCT	_	12 solid	punct
7	whereas	whereas	SCONJ	_	12 solid	mark
8	a	a	DET	Definite=Ind PronType=Art	9 mixture	det
9	mixture	mixture	NOUN	Number=Sing	12 solid	nsubj
10	is	be	AUX	Mood=Ind Number=Sing Person=3 Tense=Pres VerbForm=Fin	12 solid	cop
11	invariably	invariably	ADV	_	12 solid	advmod
12	solid	solid	ADJ	Degree=Pos	5 liquid	conj

#	verb	tense, mood	who	what, whom	to whom	where	when	other	roles by
1	is	present	a compound					invariably, liquid property	tree rules
2	is	present	a mixture					invariably, solid property	tree rules

Option 3 · ← Mova's choice · ✓ the right answer

In a compound the constituent atoms are chemically joined, whereas in a mixture they are not

The tree, 16 words

The words, one row each (CoNLL-U)

#	word	lemma	UPOS	features	head	relation
1	In	in	ADP	_	3 compound	case
2	a	a	DET	Definite=Ind PronType=Art	3 compound	det
3	compound	compound	NOUN	Number=Sing	9 joined	obl
4	the	the	DET	Definite=Def PronType=Art	6 atoms	det
5	constituent	constituent	NOUN	Number=Sing	6 atoms	compound
6	atoms	atom	NOUN	Number=Plur	9 joined	nsubj:pass
7	are	be	AUX	Mood=Ind Number=Plur Person=3 Tense=Pres VerbForm=Fin	9 joined	aux:pass
8	chemically	chemically	ADV	_	9 joined	advmod
9	joined	join	VERB	Tense=Past VerbForm=Part Voice=Pass	root	root
10	,	,	PUNCT	_	11 whereas	punct
11	whereas	whereas	ADV	_	9 joined	advmod
12	in	in	ADP	_	14 mixture	case
13	a	a	DET	Definite=Ind PronType=Art	14 mixture	det
14	mixture	mixture	NOUN	Number=Sing	9 joined	obl
15	they	they	PRON	Case=Nom Number=Plur Person=3 PronType=Prs	16 are	nsubj
16	are	be	VERB	Mood=Ind Number=Plur Person=3 Tense=Pres VerbForm=Fin	9 joined	conj
17	not	not	PART	Polarity=Neg	16 are	advmod

#	verb	tense, mood	who	what, whom	to whom	where	when	other	roles by
1	join	present · passive		the constituent atoms		a compound		in a mixture; chemically, whereas property	vn mix-22.1-2-1 «NP V NP»: subject=Patient
2	not does	present	atoms = atom						vn exist-47.1 «NP V»: agent=Theme

Option 4

A compound may be separated by a magnet, whereas a mixture may not

The words, one row each (CoNLL-U)

#	word	lemma	UPOS	features	head	relation
1	A	a	DET	Definite=Ind PronType=Art	2 compound	det
2	compound	compound	NOUN	Number=Sing	10 whereas	nsubj
3	may	may	AUX	VerbForm=Fin	5 separated	aux
4	be	be	AUX	VerbForm=Inf	5 separated	aux:pass
5	separated	separate	VERB	Tense=Past VerbForm=Part Voice=Pass	2 compound	acl
6	by	by	ADP	_	8 magnet	case
7	a	a	DET	Definite=Ind PronType=Art	8 magnet	det
8	magnet	magnet	NOUN	Number=Sing	5 separated	obl
9	,	,	PUNCT	_	2 compound	punct
10	whereas	wherea	VERB	Mood=Ind Number=Sing Person=3 Tense=Pres VerbForm=Fin	root	root
11	a	a	DET	Definite=Ind PronType=Art	12 mixture	det
12	mixture	mixture	NOUN	Number=Sing	13 may	nsubj
13	may	may	AUX	VerbForm=Fin	10 whereas	ccomp
14	not	not	PART	Polarity=Neg	13 may	advmod

#	verb	tense, mood	who	what, whom	to whom	where	when	other	roles by
1	separate	may · passive	a magnet	a compound not said here					vn separate-23.1-1-1 «NP V»: agent=Patient
2	wherea	present	a compound						tree rules

Text: the tests of Mova's primary school, written for Mova (world/data/school/), as the course runner gave them to the student. Trees: Mova's own parse — the en model on the CPU, when the site is built — not checked by a teacher; they may be wrong. Frames: Mova's frames reader (prag), each text read on its own. Elamur Cosmic License.

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