For a science fair project about food and chemistry, bill looks around his kitchen for examples of covalent compounds. what evidence can bill use in his project to show that water (h2o) acts like other covalent compounds?
a) he can demonstrate that water is a liquid with a definite volume.
b)he can demonstrate that water can be boiled on a simple kitchen stove.
c)he can demonstrate that water can sometimes be used to conduct electricity.
d)he can demonstrate that water can change shape and either be sprayed or poured.

The evidence that can demonstrate the covalent nature of water is

Further Explanation:

The bond that is formed by the mutual sharing of electrons between the bonded atoms is called a covalent bond. It is also known as a molecular bond. Covalent compounds are those compounds which are formed by the electron sharing between two or more non-metals.

Following are some of the properties of covalent compounds:

1. These are brittle solids.

2. Low melting and boiling points.

3. Poor conductors of heat and electricity.

4. Low enthalpy of fusion.

Boron trichloride , silicon dioxide   , and xenon hexafluoride   are some examples of covalent compounds.

(A). Water is a liquid that has a definite volume. The physical property can be determined without knowing the chemical nature of the substance. Therefore the liquid state of water with a fixed volume is not able to predict its chemical properties and determination of the type of compound comes under these properties. So it cannot predict the covalent nature of water. Hence, the option (A) is incorrect.

(B). Boiling of water on a kitchen stove does not allow its temperature to reach a certain higher limit. This indicates that it boils at a moderate temperature due to which it is clear that water has low boiling point. As we know, boiling points of covalent compounds are low due to the presence of weak intermolecular forces between them. This proves water is a covalent compound. Hence, the option (B) is correct

(C). Water is a covalent compound. As we know covalent compounds are formed by the mutual sharing of electrons. So their electrical conductivity of covalent compounds is very low due to the absence of free ions in them and therefore this property cannot show the covalent nature of water molecule. Hence, the option (C) is incorrect

(D). Water can change its shape and can be sprayed or poured. This shows water has some fluidity in it and has intermediate forces of attraction. But it gives no idea about whether water is a covalent compound or not. So this property cannot be used to predict the covalent nature of water molecule. Hence, the option (D) is incorrect

Learn more:

1. Identification of ionic bonding:

2. Example of physical change:

Answer details:

Grade: High School

Subject: Chemistry

Chapter: Ionic and covalent compounds

Keywords: water, covalent compound, H2O, mutual sharing, electrons, liquid, shape, volume, kitchen stove, electrical conductivity, covalent bond, molecular bond.

1. the question asks the most appropriate, which seems to rule out "all of the above." your choice appears to be the correct one.

2. the protocol described is good for identifying correlation, but not cause and effect. for cause/effect, you need to devise a protocol that will assign the treatment (or not) to groups that have essentially the same "demographics" with respect to all the other variables. your choice regarding control group seems appropriate. random assignment of treatment (choice d) may be appropriate also. (i think you can argue that b and d are just different descriptions of the same method.)

3. d will randomize the birds, but may not guarantee there are 10 in each group. e will do both, so seems the better choice.

comment on question 2

based on the problem statement, it seems clear that confident, attentive drivers are more likely to use daytime running lights. so, the protocol might need to be devised in such a way that the lights would be turned on or off without the driver's knowledge. (an attentive driver will figure it out.) assigning a confident, attentive driver to a group required to drive without running lights might mess with his/her confidence and attentiveness. you don't want your experiment to do that. (nor do you want the experiment to subject a driver to greater risk of accident as a consequence of driving without running lights.) experiments involving human safety are always problematic.