Which noble gas is radioactive and is produced as a decay product of uranium and thorium?
Argon
Krypton
Radon
Neon
Correct answer is C
Radon is a radioactive noble gas and is produced as a decay product of uranium and thorium in the Earth's crust. It is colorless, odorless, and tasteless, making it potentially hazardous when it accumulates in enclosed spaces.
The position of equilibrium shifts to the left
The position of equilibrium shifts to the right.
The position of equilibrium remains unchanged
The reaction stops
Correct answer is B
When the temperature is decreased in a reversible reaction, the equilibrium shifts in the direction that produces heat (exothermic direction). For an exothermic reaction, this means the equilibrium position shifts to the right, favoring the forward reaction.
Hard water is water with high concentrations of dissolved ions, in particular calcium and
magnesium ions
nitrogen ions
phosporus ions
helium ions
Correct answer is A
Hard water is water with high concentrations of dissolved ions, in particular calcium and magnesium ions
| GAS | CO\(_2\) | N\(_2\) |
O\(_2\) |
| % BY VOLUME | 4 | 72 | 24 |
The above table shows the compositions of the atmosphere of planet X. Which of these gases are present in higher percentages on earth?
CO\(_2\) and O\(_2\)
N\(_2\) and CO\(_2\)
CO\(_2\), O\(_2\) and N\(_2\)
O\(_2\) and N\(_2\)
Correct answer is D
The air in Earth's atmosphere is made up of approximately 78 percent nitrogen and 21 percent oxygen. Air also has small amounts of other gases, too, such as carbon dioxide, neon, and hydrogen.
30
40
20
50
Correct answer is B
To make a fixed amount of a dilute solution from a stock solution,
use the formula: C1V1 = C2V2
where: V1 = Volume of stock solution needed to make the new solution.
C1 = Concentration of stock solution.
V2 = Final volume of new solution.
C2 = Final concentration of stock solution
2 * 10 = 0.5 * V2
20 = 0.5V2
\(\frac{20}{0.5}\) = V2
= 40dm\(^3\)