Properties of Water Biology Quiz

You are a scientist working in a lab and you need to prepare a solution. You have a compound with the molecular formula H2O. What is this compound commonly known as?

• Sodium Chloride (NaCl)

• Water (H2O)

• Carbon Dioxide (CO2)

• Hydrogen Peroxide (H2O2)

Answer explanation

The question asks for the common name of a compound with the molecular formula H2O. This formula corresponds to the compound 'Water'. Other options given, Sodium Chloride (NaCl), Carbon Dioxide (CO2), and Hydrogen Peroxide (H2O2) have different molecular formulas and hence, they are not the correct answer.

John has a water bottle. If he breaks down a single molecule of water from his bottle, how many hydrogen atoms will he find?

• 2

• 4

• 1

• 3

Answer explanation

A water molecule is made up of two hydrogen atoms and one oxygen atom. Hence, if John breaks down a single molecule of water, he will find 2 hydrogen atoms. This is why the correct answer is 2.

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NGSS.MS-PS1-1

Imagine you are a scientist studying water molecules. What shape would you say a water molecule is?

• Octahedral

• Tetrahedral

• Linear

• Bent or V-shaped

Answer explanation

A water molecule is made up of two hydrogen atoms and one oxygen atom, forming a bent or V-shaped structure due to the uneven distribution of electrons. The two hydrogen atoms form an angle with the oxygen atom, leading to its bent shape.

You are a scientist working in a lab and you need to prepare a solution. What is the chemical symbol for the water you will use?

• O2H

• H2O

• HO2

• H2O2

Answer explanation

The chemical symbol for water is H2O. This is the most basic and accurate representation of the water molecule, consisting of two hydrogen atoms and one oxygen atom. The other options, O2H, HO2 and H2O2, are not correct as they do not represent the chemical structure of water.

What is the main reason for the polarity of water molecules?

• Unequal sharing of electrons

• Ionic bonding

• Covalent bonding

• Hydrogen bonding

Answer explanation

The main reason for the polarity of water molecules is the unequal sharing of electrons. This is because water molecules are polar, meaning they have a positive end and a negative end. This happens due to unequal distribution of electrons in the O-H bond, where oxygen being more electronegative pulls the electron pair closer resulting in polarity.

What type of bond holds the hydrogen atoms to the oxygen atom in a water molecule?

• covalent bond

• metallic bond

• hydrogen bond

• ionic bond

Answer explanation

In a water molecule, the hydrogen atoms are held to the oxygen atom by a covalent bond. This is a type of chemical bond where atoms share pairs of electrons. It's not a hydrogen bond, which occurs between molecules, not within. Neither is it a metallic or ionic bond which occur in metals and ions respectively.

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NGSS.MS-PS1-1

Imagine you are studying the structure of a water molecule in a science experiment. How many hydrogen bonds can this water molecule form at maximum?

• 4

• 8

• 2

• 6

Answer explanation

A water molecule, H2O, can form four hydrogen bonds at maximum. This is because each hydrogen atom can form one bond and the oxygen atom can form two bonds, making it a total of four. This explains why the correct answer to the question is 4.

Imagine you're at the beach on a hot summer day. You notice that the sand gets extremely hot, but the water remains relatively cool, even under the blazing sun. This phenomenon is due to a specific physical property of water. What is this property called?

• capillary action

• high specific heat

• high heat of fusion

• high heat of vaporization

Answer explanation

The phenomenon is due to the high specific heat of water. Specific heat is a property which determines how much heat energy is required to change the temperature. Water has a high specific heat, meaning it can absorb a lot of heat before it starts to get hot. This is why water stays relatively cool even on hot days, while the sand quickly becomes hot as it has a low specific heat.

Imagine you're boiling a pot of water for your pasta. You notice that it takes a lot of heat to turn the water into steam, even though the amount of water is small. This property of water is known as:

• capillary action

• high specific heat

• high heat of fusion

• high heat of vaporization

Answer explanation

The question refers to the property of water that requires a large amount of heat to change from liquid to gas. This is known as the high heat of vaporization. It refers to the amount of energy needed to transform a given quantity of a substance from a liquid into a gas at a given pressure.

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NGSS.MS-PS1-4

NGSS.MS-PS3-4

Imagine you are observing a lake during the winter season. You notice that the lake takes a long time to freeze completely, providing aquatic life more time to adapt to the changing temperature. What property of water is responsible for this phenomenon?

• capillary action

• high specific heat

• high heat of fusion

• high heat of vaporization

Answer explanation

The phenomenon described in the question is due to the high heat of fusion property of water. This property means that water requires a large amount of energy to change from a liquid state to a solid state, hence why it takes longer for a lake to completely freeze. This slow transition gives aquatic life more time to adapt to the changing temperature.

Tags

NGSS.MS-PS1-4