Answer:
The geologist time scale was formed when scientists studied rock layers and index fossils worldwide. With this information, they placed Earth's rocks in order by relative age. Later, radioactive dating helped determine the exact age of the divisons in the geologic time scale.
This scale is organized by the 4.6 billion years of earth's history into sections based on important changes seen in the geologic record. The largest intervals are called eons, with each eon containing many millions of years.
In precambarian time the processes that affect Earth's surface have lessened the erosion on the surface. Earth was being hit by meteorites every second. Now there is water erosion and there wasn't back then. The surface changes have lessened over time.
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.
Answer: m = 50 g ZnSO4
Explanation: First is convert the moles of Zn to the moles of ZnSO4 by having their mole ratio which is 2:2 based from the balanced equation. Next is convert the moles of ZnSO4 to mass using its molar mass.
0.311 mole Zn x 2 moles ZnSO4 / 2 moles Zn
= 0.311 moles ZnSO4
0.311 moles ZnSO4 x 161 g ZnSO4 / 1 mole ZnSO4
= 50 ZnSO4
Answer:
Formula: Na2S2O3
we get solubility.
Divide the mass of the compound by the mass of the solvent and then multiply by 100 g to calculate the solubility in g/100g .
Solution given:
mass of sodium thiosulphate [m1]=25.5g
mass of water [m2]=40g
at temperature [t]=25°C
we have
<u>solubility in g/dm^3</u> :
- =
- =63.75g /litre=63.75g/dm³
<u>solubility in g/dm^3 :63.75g/dm³</u>
<u>n</u><u>o</u><u>w</u>
solubility of the solute in mol/dm^3=:63.75g/dm³/178=0.4 mol/dm³
Nitrogen. air consists 78% of nitrogen gas
