Answer:
15.4: Lewis Structures: Counting Valence Electrons
Explanation:
Answer:
Water (H2O) is polar because of the bent shape of the molecule. The highly electronegative oxygen atom attracts electrons or negative charge to it, making the region around the oxygen more negative than the areas around the two hydrogen atoms.
Rock is a combination of two or more minerals, and it does not possess any specific chemical composition. It is present naturally in the environment. Some examples of rocks are limestone, granite, etc.,Limestone may contain minerals like calcite and aragonite. Each mineral has a specific chemical composition with a well defined crystalline structure.
Therefore, the correct option would be a. rock as rock is the naturally occurring solid mass made up of different types of minerals.
<span>14.2 grams
Let's start by looking up the atomic weights of aluminum and oxygen.
Atomic weight aluminum = 26.981539
Atomic weight oxygen = 15.999
Moles Al = 7.5 g / 26.981539 g/mol = 0.277967836
The formula for aluminum oxide is Al2O3, so for every 2 moles of Al, 3 moles of O is required. So let's calculate the number of moles of O we need and from that the mass.
0.277967836 mol / 2 * 3 = 0.416951754 mol
Mass O2 = 0.416951754 * 15.999 = 6.670811105
The mass of aluminum oxide is simply the mass of aluminum plus the mass of oxygen. So:
7.5 g + 6.670811105 g = 14.17081111 g
Rounding to 1 decimal place gives 14.2 g.</span>
