Answer:
Explanation:
Both diamond and graphite are made entirely out of carbon.In a diamond, the carbon atoms are arranged tetrahedrally. Each carbon atom is attached to four other carbon with a C-C-C bond angle of 109.5 degrees. It is a strong, rigid three-dimensional structure that results in an infinite network of atoms. This accounts for diamond's hardness, extraordinary strength and durability and gives diamond a higher density than graphite. Because of its tetrahedral structure, diamond also shows a great resistance to compression. Diamond will scratch all other materials and is the hardest material known. It is the best conductor of heat that we know, conducting up to five times the amount that copper does. Diamond also conducts sound, but not electricity; it is an insulator, and its electrical resistance, optical transmissivity and chemical inertness are correspondingly remarkable.
The carbon atoms in graphite are also arranged in an infinite array, but they are layered. These atoms have two types of interactions with one another. In the first, each carbon atom is bonded to three other carbon atoms and arranged at the corners of a network of regular hexagons with a 120-degree C-C-C bond angle. These planar arrangements extend in two dimensions to form a horizontal, hexagonal "chicken-wire" array. In addition, these planar arrays are held together by weaker forces. The distance between two layers is longer than the distance between carbon atoms within each layer. This three-dimensional structure accounts for the physical properties of graphite. Unlike diamond, graphite can be used as a lubricant or in pencils because the layers cleave readily. It is soft and slippery, and its hardness is less than diamond . Graphite also has a lower density (2.266 grams per cubic centimeter) than diamond. The planar structure of graphite allows electrons to move easily within the planes. This permits graphite to conduct electricity and heat as well as absorb light and, unlike diamond, appear black in color.
No not all. for example cutting down a tree is a physical reaction/change but it is not something you can redo.
•A wave produced by the acceleration of an electric charge and propagated by the periodic variation of intensities of, usually, perpendicular electric and magnetic fields
In other words : They are radio waves, microwaves, visible light, and x rays are all examples of electromagnetic waves
They are produced by the motion of electrically charged particles.
I hope this helped ! :)
Answer:
Explanation:
Na + Cl = NaCl
23 g 35.5 g
23 g sodium reacts with 35.5 g of chlorine
29 g of sodium reacts with 35.5 x 29 / 23 g of chlorine
= 44.76 g
So 44.76 g of chlorine reacts and 49 - 44.76 = 4.24 g of chlorine is left over .
All the sodium is used up in the reaction .
Answer:
8.1g
0.1g
Explanation:
The reaction expression is given as:
Fe + 2HBr → FeBr₂ + H₂
Mass of pure iron given = 2.8g
A. Mass of HBr needed to dissolve a padlock of the mass;
To solve this problem, we need to use the mole concept.
Convert mass of the known iron to the number of moles.
Number of moles = 
Molar mass = 56g/mol
Number of moles of iron = 
= 0.05mole
1 mole of Fe will react with 2 mole of HBr
0.05mole of Fe will react with 0.05 x 2 = 0.1mole of HBr
Mass of HBr = number of moles x molar mass
Molar mass of HBr = 1 + 80 = 81g/mol
Mass of HBr = 0.1 x 81 = 8.1g
B. What mass of H2 would be produced by the complete reaction of the iron bar
Since:
1 mole of Fe will produce 2 mole of hydrogen gas
0.05mole of Fe will produce 2 x 0.05mole = 0.1mole of hydrogen gas
Mass of hydrogen gas = number of moles x molar mass
= 0.1 x 1
= 0.1g
