<span> the atmosphere holds about 21 per cent oxygen. Over the Earth’s 4.6 billion year history, oxygen did not appear in the atmosphere until perhaps about 2.5 billion years ago. Since then, oxygen levels have fluctuated in tandem with global geological and biological events, such as mass extinctions.</span>
Answer:
magnesium chloride (no prefixes)
The closer to the top the metal is in the list, the more active the metal is and the stronger a reducing agent the metal is. When two different metals are involved in a redox reaction, the metal higher in the list will be oxidized and give up electrons that will reduce the cation of the less active metal.
Answer:
The original volume of the gas is 0.001 mL
Explanation:
This easy excersise can be solved by the law for gases, about pressure and volume; the volume of a gas is inversely proportional to the pressure it exerts.
We can propose the rule by this formula:
P₁ / V₁ = P₂ / V₂
We replace data given: 1.50 atm / V₁ = 0.50 atm / 750 mL
As the rule says, that volume is inversely proportional, and the pressure was decreased, volume must be lower than 750 mL.
1.5atm / (0.5 atm / 750mL) = V₁
V₁ = 0.001 mL
