Model Simple Molecules - Middle School Physical Science
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What does a different color or label in a particle model usually represent?
What does a different color or label in a particle model usually represent?
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A different element (a different type of atom). Different colors/labels distinguish between different atomic elements in models.
A different element (a different type of atom). Different colors/labels distinguish between different atomic elements in models.
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What does a line or “stick” between atoms represent in a particle model of a molecule?
What does a line or “stick” between atoms represent in a particle model of a molecule?
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A chemical bond holding the atoms together. Lines show atoms are connected by sharing or transferring electrons.
A chemical bond holding the atoms together. Lines show atoms are connected by sharing or transferring electrons.
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What is the meaning of the subscript in a chemical formula such as $H_2$?
What is the meaning of the subscript in a chemical formula such as $H_2$?
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It shows the number of atoms of that element in one molecule. Subscripts count how many atoms of that element exist in the molecule.
It shows the number of atoms of that element in one molecule. Subscripts count how many atoms of that element exist in the molecule.
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Identify how many oxygen atoms are in one molecule of $H_2O$.
Identify how many oxygen atoms are in one molecule of $H_2O$.
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$1$ oxygen atom. No subscript on $O$ means exactly $1$ oxygen atom.
$1$ oxygen atom. No subscript on $O$ means exactly $1$ oxygen atom.
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Which formula matches a particle model with $1$ carbon atom bonded to $4$ hydrogen atoms?
Which formula matches a particle model with $1$ carbon atom bonded to $4$ hydrogen atoms?
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$CH_4$. Methane has $1$ C atom bonded to $4$ H atoms.
$CH_4$. Methane has $1$ C atom bonded to $4$ H atoms.
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What does it mean if an element symbol has no subscript in a formula (for example, the $O$ in $H_2O$)?
What does it mean if an element symbol has no subscript in a formula (for example, the $O$ in $H_2O$)?
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It means there is $1$ atom of that element in the molecule. No subscript is understood as subscript $1$ by convention.
It means there is $1$ atom of that element in the molecule. No subscript is understood as subscript $1$ by convention.
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Which term names a molecule made of two or more different elements chemically bonded?
Which term names a molecule made of two or more different elements chemically bonded?
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A compound. Compounds contain atoms of different elements bonded together.
A compound. Compounds contain atoms of different elements bonded together.
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Which term names a molecule made of only one element type (for example, $O_2$)?
Which term names a molecule made of only one element type (for example, $O_2$)?
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An elemental molecule (a molecule of an element). Contains only one type of element, like diatomic oxygen.
An elemental molecule (a molecule of an element). Contains only one type of element, like diatomic oxygen.
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What is the total number of atoms in one molecule of $CO_2$?
What is the total number of atoms in one molecule of $CO_2$?
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$3$ atoms total. $1$ carbon plus $2$ oxygen equals $3$ atoms.
$3$ atoms total. $1$ carbon plus $2$ oxygen equals $3$ atoms.
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Which formula matches a particle model with $2$ hydrogen atoms bonded to $1$ oxygen atom?
Which formula matches a particle model with $2$ hydrogen atoms bonded to $1$ oxygen atom?
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$H_2O$. Water has $2$ H atoms bonded to $1$ O atom.
$H_2O$. Water has $2$ H atoms bonded to $1$ O atom.
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What is the ratio of hydrogen atoms to oxygen atoms in $H_2O$?
What is the ratio of hydrogen atoms to oxygen atoms in $H_2O$?
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$2:1$. $2$ hydrogen atoms for every $1$ oxygen atom.
$2:1$. $2$ hydrogen atoms for every $1$ oxygen atom.
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Which formula matches a particle model with $1$ nitrogen atom bonded to $3$ hydrogen atoms?
Which formula matches a particle model with $1$ nitrogen atom bonded to $3$ hydrogen atoms?
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$NH_3$. Formula shows $1$ N bonded to $3$ H atoms.
$NH_3$. Formula shows $1$ N bonded to $3$ H atoms.
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What is the total number of atoms in one molecule of $NH_3$?
What is the total number of atoms in one molecule of $NH_3$?
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$4$ atoms total. $1$ nitrogen plus $3$ hydrogen equals $4$ atoms.
$4$ atoms total. $1$ nitrogen plus $3$ hydrogen equals $4$ atoms.
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What does the coefficient mean in $2H_2O$ compared with $H_2O$?
What does the coefficient mean in $2H_2O$ compared with $H_2O$?
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It means $2$ molecules of $H_2O$. Coefficients multiply entire molecules, not individual atoms.
It means $2$ molecules of $H_2O$. Coefficients multiply entire molecules, not individual atoms.
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Find the number of each atom type in $C_6H_{12}O_6$.
Find the number of each atom type in $C_6H_{12}O_6$.
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$6$ C, $12$ H, $6$ O. Multiply each element by its subscript to count atoms.
$6$ C, $12$ H, $6$ O. Multiply each element by its subscript to count atoms.
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Identify the correct formula for a molecule with $2$ nitrogen atoms and $4$ oxygen atoms.
Identify the correct formula for a molecule with $2$ nitrogen atoms and $4$ oxygen atoms.
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$N_2O_4$. Subscripts indicate atom counts in the molecule.
$N_2O_4$. Subscripts indicate atom counts in the molecule.
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Identify the correct formula for a molecule with $2$ carbon atoms and $6$ hydrogen atoms.
Identify the correct formula for a molecule with $2$ carbon atoms and $6$ hydrogen atoms.
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$C_2H_6$. Subscripts show the count of each element type.
$C_2H_6$. Subscripts show the count of each element type.
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What is the ratio of carbon atoms to oxygen atoms in $CO_2$?
What is the ratio of carbon atoms to oxygen atoms in $CO_2$?
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$1:2$. $1$ carbon atom for every $2$ oxygen atoms.
$1:2$. $1$ carbon atom for every $2$ oxygen atoms.
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How many atoms total are in one molecule of C$_2$H$_6$?
How many atoms total are in one molecule of C$_2$H$_6$?
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$8$ atoms. Count: $2$ carbon + $6$ hydrogen = $8$ total.
$8$ atoms. Count: $2$ carbon + $6$ hydrogen = $8$ total.
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What is the total number of atoms in one molecule of NH$_3$?
What is the total number of atoms in one molecule of NH$_3$?
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$4$ atoms. Count: $1$ nitrogen + $3$ hydrogen = $4$ total.
$4$ atoms. Count: $1$ nitrogen + $3$ hydrogen = $4$ total.
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What is the total number of atoms in one molecule of CO$_2$?
What is the total number of atoms in one molecule of CO$_2$?
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$3$ atoms. Count: $1$ carbon + $2$ oxygen = $3$ total.
$3$ atoms. Count: $1$ carbon + $2$ oxygen = $3$ total.
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What does the coefficient in front of a formula (for example, $3$H$_2$O) represent?
What does the coefficient in front of a formula (for example, $3$H$_2$O) represent?
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The number of molecules (or formula units). Coefficients multiply entire formulas, not individual atoms.
The number of molecules (or formula units). Coefficients multiply entire formulas, not individual atoms.
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What does it mean if an element symbol in a formula has no subscript (for example, O in CO$_2$)?
What does it mean if an element symbol in a formula has no subscript (for example, O in CO$_2$)?
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There is $1$ atom of that element in the molecule. No subscript means exactly one atom of that element.
There is $1$ atom of that element in the molecule. No subscript means exactly one atom of that element.
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Identify what the subscript in a chemical formula (for example, H$_2$O) tells you.
Identify what the subscript in a chemical formula (for example, H$_2$O) tells you.
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The number of atoms of that element in one molecule. Subscripts count atoms per molecule, not total molecules.
The number of atoms of that element in one molecule. Subscripts count atoms per molecule, not total molecules.
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Which feature in a model shows that atoms are different elements: size, color, or both?
Which feature in a model shows that atoms are different elements: size, color, or both?
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Both color and size can indicate different elements. Models use visual differences to distinguish elements.
Both color and size can indicate different elements. Models use visual differences to distinguish elements.
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