My Friday is going good and I might get to go over to my BFF house!!!
Answer:
Explanation:
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In this case, considering that the mass of hydrazine is missing, we can assume it is 130.0 g (a problem found on ethernet). In such a way, since we need a mass-mole-atoms relationship by which we can compute moles of hydrazine given its molar mass (32.06 g/mol), then the moles of hydrogen considering one mole of hydrazine has four moles of hydrogen and one mole of hydrogen has 6.022x10²³ atoms (Avogadro's number); therefore, we proceed as shown below:
Notice 130.0 g has four significant figures, therefore the result is displayed with four as well.
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Answer:
See Explanation
Explanation:
1) Let us recall that;
Mass number = number of protons + number of neutrons
Where;
Number of protons = ?
Number of neutrons =20
Mass number =39
Number of protons = mass number - number of neutrons
Mass of protons =39 - 20= 19 protons
2) Atomic number = 13
Number of neutrons =14
Then the mass number =13 +14 =27
The symbol of the element is 27X13
The number of protons= the number of electrons =13
The atomic number is the same as the proton number =13
<span>That the mass is far lesser
and distributed mistakenly, as compared to what the orbits of stars declare it
should be. Stars orbit more rapidly than the mass would predict, particularly
out toward the galactic edge. This means that there is more mass than has been
measured, and that it is spread out in a huge cloud around the galaxy. This is
one of the reasons why scientists believe that dark matter exists.</span>
