Answer:
B) 82 protons
Explanation:
The number of protons for an element never change. 82 Is the atomic number for Pb which is how many protons it has. An isotope means it has more neutrons.
It uses the voltages and sound freq. in the air to measure the wave lengthths
Answer:
The answer to your question is 27 g of Al
Explanation:
Data
mass of Al = ?
moles of Al₂O₃ = 0.5
The correct formula for the product is Al₂O₃
Balanced chemical reaction
4Al + 3O₂ ⇒ 2Al₂O₃
Process
1.- Calculate the molar mass of the product
Al₂O₃ = (27 x 2) + (16 x 3)
= 54 + 48
= 102 g
2.- Convert the moles of Al₂O₃ to grams
102 g ---------------- 1 mol
x ---------------- 0.5 moles
x = (0.5 x 102) / 1
x = 51 g of Al₂O₃
3.- Use proportions to calculate the mass of Al
4(27) g of Al --------------- 2(102) g of Al₂O₃
x --------------- 51 g
x = (51 x 4(27)) / 2(102)
x = 5508 / 204
x = 27 g of Al
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.
The best answer for this question would be B
