Answer:
Percentage mass of copper in the sample = 32%
Explanation:
Equation of the reaction producing Cu(NO₃) is given below:
Cu(s)+ 4HNO₃(aq) ---> Cu(NO₃)(aq) + 2NO₂(g) + 2H₂O(l)
From the equation of reaction, 1 mole of Cu(NO₃) is produced from 1 mole of copper. Therefore, 0.010 moles of Cu(NO₃) will be produced from 0.010 mole of copper.
Molar mass of copper = 64 g/mol
mass of copper = number of moles * molar mass
mass of copper = 0.01 mol * 64 g/mol = 0.64 g
Percentage by mass of copper in the 2.00 g sample = (0.64/2.00) * 100%
Percentage mass of copper in the sample = 32%
During the past two million years, glaciers have shaped and reshaped the surface of Ohio several times. These continental masses of ice affected as much as two-thirds of the state. Moving from the north and northwest, glaciers have scraped and flattened the landscape. Often more than a mile thick, they smoothed existing hills and filled valleys with enormous amounts of rocks, gravel, and smaller particles. Through these actions, glaciers have had a very important impact on the agriculture of Ohio. Their activity has been felt in two noticeable ways: shaping the ground upon which people work and build, and forming the soils that cover that ground.
Answer: 4.35%
Explanation:
Scientists estimate that the current composition of gases in the Earth's atmosphere has been stable for the last 200 million years or so.
If the Earth was formed 4,600 million years ago then the percentage of her age that the atmosphere has been in its composition is:
= 200 / 4,600 * 100%
= 4.35%
