Answer:
C. United States, Russia, and China
Explanation:
Only three nations (Russia, U.S., China) have launched their own crewed spacecraft, with the Soviets/Russians and the American programs providing rides to other nations' astronauts. Twenty-seven "first flights" occurred on Soviet or Russian flights while the United States carried fourteen.
Answer:
answer is b
use pv=nRT
p directly proportional to moles(n)
p1/p2=n1/n2
p/p2=n/2n
p2=2p
Answer:
When observing how thallium reacts with the air of the earth's atmosphere, its hardness or resistance resembled sodium, it was not investigated further to classify it correctly
Explanation:
Now it is known that they contain different numbers of valence electrons and that thallium is a heavy metal like lead and that they have similar characteristics except for their melting point where thallium is higher.
Answer:
8.60 * 
atoms N2
Explanation:
We want to convert grams to moles and then moles to atoms.
First, we convert grams of nitrogen gas (which is N2) to moles. To do so, we need the molar mass of N2, which is just 14.01 * 2 = 28.02 g.
40 g N2 * 
= 1.43 mol N2
Now, we need to convert moles to atoms by using Avogadro's number, which is 
:
1.43 mol N2 * 
= 8.60 * atoms N2
Thus, the answer is 8.60 * atoms N2.
Answer:
2.12×10²³ atoms.
Explanation:
From Avogadro's hypothesis, we understood that 1 mole of any substance contains 6.02×10²³ atoms. This simply means that 1 mole of zirconium also 6.02×10²³ atoms.
Thus, we can obtain the number of atoms present in 0.3521 mole of zirconium as follow:
1 mole of zirconium also 6.02×10²³ atoms.
Therefore, 0.3521 mole of zirconium will contain = 0.3521 × 6.02×10²³ = 2.12×10²³ atoms.
Therefore, 0.3521 mole of zirconium contains 2.12×10²³ atoms.
