Releases heat
(Exothermic)
A rain gauge<span> (also known as an udometer, pluviometer, or an ombrometer) is an instrument used by meteorologists and hydrologists to gather and measure the amount of liquid precipitation over a set period of time.
i hope that helps</span>
Answer:
litmus paper turns red under acidic conditions
Explanation:
<span>These are five questions and five answers.
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</span><span>1. A substance that can be separated into two or more substances only by a chemical change is a.</span><span /><span />
<span>Answer: compound
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<span>Explanation:
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<span>i) solution is a homogenous mixture and it can be separated by physical media. For example, a brine: you can evaporate the water from the salt by heating the solution (brine)
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<span>ii) elements cannot be separated into two or more substances except by nuclear reactions.
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<span>iii) mixtures: heterogenous and homogenous mixtures can be separated by physical treatments.
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<span>iv) compounds are substaces composed of different elements bonded chemically; only chemical reactions break the chemical bonds or create new chemical bonds leading a compound to form other substances.
2. Which of the following materials is a substance?
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<span>Answer: silver
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<span>Explanation:
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</span><span>Substances have a definite composition that can only be modified by chemical reactions.
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</span><span>Elements and compounds are substances.
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</span><span>Silver is an element, such as sodium, gold, oxygen. You can find the list of the 118 known elements in a periodic table.
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</span><span>Mixtures, either homogenous or heterogeneous, can be separated by physical mechanisms and so they are not substances: air, gasoline, and stainless steel are mixtures because they have not a unique chemical formula but are formed by other compounds or elements in different proportions, i.e. with not a unique chemical formula.</span><span /><span>
3.The first figure in a properly written chemical symbol always is _____.
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<span>Answer: capitalized
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<span>Explanation:
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</span><span>This is a rule to write the symbols of the elements. For example, Na (sodium), Br (bromine), I (iodine), O (oxygen), Ne (neon).</span><span /><span>
4. Which of the following represents a compound?
Answer: H2O
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</span><span>Explanation:
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</span><span>That is the only chemical formula. The other representations are not valid chemical formulas. A chemical cormula can oly contain chemical symbols and subscript numbers, to represent the kind of atoms (elements) and how many of each (the subscrip).</span><span /><span>
5. What do chemical symbols and formulas represent, respectively?
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<span>Answer: elements and compounds
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<span>Justification:
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<span>1) The symbols are used to represnt elements, such as Na (sodium), Li (lithium), Be (berylium)
2) Chemical formulas represent compunds. For example: CO is carbon monoxide, CO2 is carbon dioxide, H2CO3 is carbonic acid, Na2CO3 is sodium carbonate.
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<span>Each compound has a unique chemical formula.
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