-Pencils were first used in 1662.
-Graphite is a crystalline form of the element carbon with its atoms arranged in a hexagonal structure.
- HB is a graphite hardness/grading scale: the higher the number next to H, the harder and lighter/less dark the pencil lead is.
- The H stands for “hard.”
Answer:
Explanation:
a drum, which makes sound when a mallet hits its surface
a cymbal, which makes sound when it is crashed against another cymbal
Answer:
(2) Molecules of I2 are polar, and molecules of Br2 are nonpolar.
(3) Molecules of Br2 have stronger intermolecular forces than molecules of I2.
(4) Molecules of I2 have stronger intermolecular forces than molecules of Br2.
None
Explanation:
Leaf stomates are the primary sites of transpiration and consist of two guard cells that form a small pore on the surfaces of leaves. The guard cells control the opening and closing of the stomates in response to various environmental stimuli and can regulate the rate of transpiration to reduce water loss.
