Try to use this link https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4455825/
Another type of weathering that attacks rocks is chemical weathering, a process that breaks down rock through chemical changes. The causes of chemical weathering include action of water, oxygen, carbon dioxide, living organisms, and acid rain. Chemical weathering can produce new minerals as it breaks down rock.
Explanation:
Answer:
Option d. is correct
Explanation:
Nitromethane is an organic compound that can be used as a fuel booster in rockets. Its chemical formula is 
.
This compound is produced as a result of reaction of sodium chloroacetate with sodium nitrite in aqueous solution.
The electron-dot structure of a nitromethane molecule shows 
charge on the nitrogen.
Option d. is correct
Answer:
A boundary is a real or imaginary line that separates two things. In geography, boundaries separate different regions of the Earth.The most obvious type of boundary is a physical boundary. A physical boundary is a naturally occurring barrier between two areas. Rivers, mountain ranges, oceans, and deserts can all serve as physical boundaries. Many times, political boundaries between countries or states form along physical boundaries. For example, the boundary between France and Spain follows the peaks of the Pyrenees Mountains, while the Alps separate France from Italy.
The Strait of Gibraltar is the boundary between southwestern Europe and northwestern Africa. This narrow waterway between the Atlantic Ocean and the Mediterranean Sea is an important political, economic, and social boundary between the continents.
Rivers are common boundaries between nations, states, and smaller political units such as counties. The Rio Grande forms a large part of the boundary between Mexico and the United States. The Mississippi Riveris the defining boundary between many of the states it winds through, including Iowa and Illinois, Arkansas and Tennessee, and Louisiana and Mississippi.
Empirical formula is the simplest ratio of whole numbers of components in a compound
calculating for 100 g of compound
C H O
mass 64.27 g 7.19 g 28.54 g
number of moles 64.27 g / 12 g/mol 7.19 g/1 g/mol 28.54 g / 16 g/mol
= 5.356 mol = 7.19 mol = 1.784 mol
divide by least number of moles
5.356 / 1.784 7.19 / 1.784 1.784 / 1.784
= 3.002 4.03 = 1.000
rounded off to nearest whole number
C - 3
H - 4
O - 1
empirical formula - C₃H₄O
mass of empirical formula = 12 g/mol x 3 + 1 g/mol x 4 + 16 g/mol x 1 = 56 g
molecular mass = 168.19 g/mol
molecular formula is the actual ratio of elements making up the compound
number of empirical units = molar mass of molecule / empirical mass
empirical units = 168.19 g/mol / 56 g = 3.00
there are 3 empirical units making up the molecular formula
molecular formula = 3 x C₃H₄O
molecular formula = C₉H₁₂O₃
