1. Classify the following substance as mixtures or compound:
a. air
b. CO
c. SnF2
d. Pure Water
2. Explain why silver iodide, AgI, a compound used in photography, has much higher melting point than vanillin, C8H8O3, a sweet-smelling compound used in flavorings.
3. Describe how to draw a ball-and-stick model of a boron trifluoride, BF3, molecule. In this molecule, a boron atom is attached to three fluorine atoms. Each F-B-F bond angles is 120 degrees, and all B-F bonds are the same length.
Example: O----O
|
O
4. Predict which molecules have a greater attraction for each other, C3H8O molecules in liquid rubbing alcohol or Ch4 molecules in methane gas.
5. Explain why glass, which is made mainly of SiO2, is ofter used to make cookware. (Hint: What properties does SiO2 have because of its structure?)
6. Predict whether a compound made of molecules that melts at -77°C is a solid, a liquid, or a gas at room temperature.
7. A picometer (pm) is equal to 1 X 10-^12 m. O-H bond lengths in water are 95.8 pm, while S-H bond lengths in dihydrogen sulfide are 135 pm. Why are S-H bond lengths longer than O-H bond lengths? (Hint: Which is larger, a sulfur atom or an oxygen atom?)
Answers & Comments
Verified answer
1. a. mixture
b. compound
c. compound
d. compound
I know the answers but i dont remeber them right now.
1. The difference between molecule and an element is that a molecules is in two elements. for eg. O2 for oxygen, as for an element it would be just O. O2 basically means that there are 2 oxygen atoms. 2.The difference between and element and a compound is that an element is made up of one atom but as for a compound it has for that one element. An example of a compound is CO2, where elements of Carbon and Oxygen is present. 3.The difference between molecules and compound is similar to no. 2, compound has 2 or more elements and for molecules has 2 or more atoms of the same element.