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ANSWER:</h2>
The Freedman's Bureau wanted to help newly freed slaves participate in American society.
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EXPLANATION:</h2>
The Freedmen's Bureau, formally known as the Bureau of Refugees, Freedmen and Abandoned Lands, was set up in 1865 by Congress to help a large number of previous dark slaves and poor whites in the South in the outcome of the Civil War. The Freedmen's Bureau given nourishment, lodging, and therapeutic guide built up schools and offered lawful help. It additionally endeavored to settle previous slaves ashore appropriated or surrendered amid the war. Be that as it may, the department was kept from completely doing its projects because of a lack of assets and faculty, alongside the legislative issues of race and Reconstruction.
Mixing calcium carbonate and HCl.
Heating copper sulfate pentahydrate.
Mixing potassium iodide and lead nitrate.
Combining magnesium and hcl.
Burning the candle.
Let's look at the available options and see what are chemical changes and what are physical changes. As a side note, line breaks, capitalization, and punctuation are VERY important. I spent almost as much time attempting to actually figure out what your options were as I spent in distinguishing between what were chemical reactions and physical changes.
Crushing calcium carbonate.
* This is a mere physical change. You start with large pieces of calcium carbonate and end up with smaller pieces. So this is a bad choice.
Mixing calcium carbonate and HCl.
* This is a chemical reaction where the calcium carbonate and hydrochloric acid react with each other and produce carbon dioxide plus other compounds. So this is a good choice.
Boiling water.
* Another physical change from liquid to vapor. You can cool down the resulting vapor and end up with the original water. So this is a bad choice.
Heating copper sulfate pentahydrate.
* This is a chemical change in that you're converting CuSO4 . 5H2O(s) into CuSO4 and H2O. So this too is a good choice.
Separating iron filing and sulfur.
* You start out with iron filings and sulfur and end up with iron filings and sulfur. Things are a bit more orderly, but no chemical reactions have occurred. So this is a bad choice.
Mixing potassium iodide and lead nitrate. * You start with 2 white solids and upon mixing them, you get a yellow solid.
A chemical reaction has occurred. So this is a good choice.
Combining magnesium and hcl.
* When you combine these two items, you get hydrogen gas as a product. So you have a chemical reaction. And this is a good choice.
Burning the candle.
* Another chemical reaction. The wax combines with the oxygen in the air and produces water vapor and carbon dioxide. So this is a good choice.
The reactant is dissolved in water
A gas and a liquid are produced
Answer:
0.001968 M min-1
Explanation:
NH2NO2(aq) --> N2O(g) + H2O(l)
[NH2NO2],M 0.978 0.476 0.232 0.113
time, min 0 255 510 765
The average rate of disappearance over the time period form t = 0 min to t = 255 min is given as;
Average rate = Change in concentration / time taken
Change in concentration = Final Concentration - Initial concentration
Change = 0.476 - 0.978 = 0.502
time taken = 255min - 0min = 255 min
Average rate = 0.502 / 255 = 0.001968 M min-1