1. Decreases by 4. (B)
2. The atomic number changes. (B)
3. 56/26 Fe. (C)
4. Potassium-40;t1/2=25 days. (B)
5. Takes place in the upper atmosphere. (A)
Answer:
Bulk matter can exist in three states: gas, liquid, and solid. Gases have the lowest density of the three, are highly compressible, and fill their containers completely
Explanation:
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The molecules of hydrogen gas that are formed is when 48.7 g of sodium are added to water is 6.375 x 10²³ molecules
<u><em>calculation</em></u>
2 Na +2H₂O → 2 NaOH +H₂
Step 1: find the moles of sodium (Na)
moles =mass÷ molar mass
from periodic table the molar mass of Na = 23 g/mol
moles= 48.7 g÷ 23 g/mol =2.117 moles
Step 2:use the mole ratio to determine the moles of H₂
from given equation Na:H₂ is 2:1
therefore the moles of H₂ = 2.117 moles x 1/2=1.059 moles
Step 3: find the molecules of H₂ using the Avogadro's law
According to Avogadro's law 1 mole = 6.02 x 10²³ molecules
1.059 moles = ? molecules
by cross multiplication
= [(1.059 moles x 6.02 x10²³ molecules) / 1 mole] =6.375 x 10²³ molecules
