Alfred Wegener
Explanation:
Alfred Wegener in 1912, proposed the theory of continental drift from his careful studies of different land masses. From his observations, he suggested the following:
- Some fossils of tropical plants were found in polar and temperate regions.
- Fossils of mesosaurus were found in South America and South Africa now separated by the Atlantic ocean.
- He fitted the continents into a giant land mass puzzles.
- Coal beds in Europe were similar to those in United States.
- Mountain chains in the edge of West Africa was similar to that of Eastern part of South America.
His theory lacked a mechanism which facilitated the plate movement.
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Answer:
The answer to your question is 6.0M, I know that you said it was not the answer, but it is. Check the significant figures.
Explanation:
Data
Molarity = ?
volume of HCl = 50 ml
volume of NaOH = 4 M
volume = 75 ml
Balanced chemical reaction
HCl + NaOH ⇒ NaCl + H₂O
Process
1.- Calculate the moles of NaOH
Molarity = moles/volume
moles = Molarity x volume
moles = 4 x 0.075
moles = 0.3 of NaOH
2.- Use proportions to calculate the moles of HCl
1 mol of NaOH ----------------- 1 mol of HCl
0.3 moles of NaOH ---------- x
x = (0.3 x 1)/1
x = 0.3 moles of HCl
3.- Calculate the molarity of HCl
Molarity = 0.3/0.05
Molarity = 6.0 M
Two hydrogens
Oxygen needs two electrons to fill its outermost electron shell. Hydrogen has one electron to play with. Therefore, an oxygen atom needs two hydrogens to bond to in order to complete its shell.
