Answer:
i also need the is question help!!!
Explanation:
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: When a substance is pure, it is composed of one type of molecule. For example, table salt is only composed of (more or less) salt molecules, while seawater has water and salt molecules. A more complicated example of a non - pure substance is soil. It has many different types of nutrients and compounds.
Answer: 3 times as much the potential energy
Explanation:
Potential energy is the energy possessed by an object by virtue of its position.

m= mass of object
g = acceleration due to gravity
h = height of an object
When same object with same is lifted from 10 feet to 30 feet. The height has increased 3 times , thus the potential energy will also get 3 times as much.
Answer:
3.0 moles Al₂O₃
Explanation:
We do not know which of the reactants is the limiting reactant. Therefore, you need to convert both of the given mole values into the product. This can be done using the mole-to-mole ratio made up of the balanced equation coefficients.
4 Al + 3 O₂ -----> 2 Al₂O₃
6.0 moles Al 2 moles Al₂O₃
---------------------- x ------------------------- = 3.0 moles Al₂O₃
4 moles Al
4.0 moles O₂ 2 moles Al₂O₃
---------------------- x ------------------------- = 2.7 moles Al₂O₃
3 moles O₂
As you can see, O₂ produces the smaller amount of product. This means O₂ is the limiting reactant. Remember, the limiting reactant is the reactant which runs out before the other reactant(s) are completely reacted. As such, the actual amount of Al₂O₃ produced is 2.7 moles.
However, since this problem is directly addressing how much Al₂O₃ is produced from Al, the answer you most likely are looking for is 3.0 moles Al₂O₃.