Answer:
Explanation:
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In this case, since the decomposition of potassium chlorate is:
We can see a 2:3 mole ratio between potassium chlorate and oxygen (molar mass 32.0 g/mol), thus, via stoichiometry, we compute the mass of oxygen that are produced by the decomposition of 2.50 moles of this reactant:
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Answer:
a weighing balance, a measuring cylinder, a spatula, a beaker/flask, and a stirrer
Explanation:
The lab apparatus that would be needed to prepare a solution of sodium chloride would be <em>a weighing balance, a measuring cylinder, a spatula, a beaker/flask, and a stirrer.</em>
The weighing balance would be used to weigh out the required amount of sodium chloride. The beaker or flask would be placed on the weighing balance and its weight zeroed. The spatula would then be sued to take out the sodium chloride from its container into the beaker till the required amount is reached. The measuring cylinder would then be used to measure out the required volume of water which would be added to the salt in the beaker. The stirrer would then be used to stir the mixture in order for the salt to dissolve.
Answer:
- <em><u>Mendeleev produced the first orderly arrangement of known elements.</u></em>
- <em><u>Mendeleev used patterns to predict undiscovered elements.</u></em>
Explanation:
- <u>Mendeleev produced the first orderly arrangement of known elements and used patterns to predict the undiscovered elements.</u>
Those two statments are true.
For the time being there were some 62 known elements. Before Medeleev some schemes to order part of the elements were proposed, but Medeleev showed the relationship between the atomic mass and the properties of the elements (supports second choice). This arrangement is known as the periodic table.
More importantly, Mendeleev predicted correctly the existance and properties of unknown elements, which is his major contribution: he left blanket spaces which where gradually filled when new elements where discovered (this supports the fourth choice).
The first modern chemistry book was written by Antoine Lavoisier (this discards first option).
Mendeleev ordered the elements by increasing mass number (this discards third choice), which was corrected later by the scientist Henry Moseley, who ordered the elements by increasing atomic number (number of protons).
Isotopes were not known by Mendeleev times, so this discards the last option.
FALSE
Organisms may play only one role in an ecosystem. ... Each of the organisms in an ecosystem fills the energy role of producer, consumer, or decomposer.
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The process to create a protected area takes a long time because there's numerous things that have to be taken in account and sorted out before the area gets that kind of legal status.
Usually there's people living in the area that is supposed to be protected, though it is mostly small settlements. The people living there are connected with that area, use the resources, and their lives are largely based and dependent on it. In order for any problems to be avoided, these people should all be educated, deals to be made with them, and properly negotiated so that the area wouldn't have any damage, but also them to be able to sustain themselves.
The boundaries of the area are also complicated, it it takes time to sort out what parts should be included and what not. Basically to set the priorities.
People should be employed to protect and take care of the area, so they have to undergo a training, education, and to get familiar with it.
The legalization of the area as such can sometimes too make problems and take some time.
