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mihalych1998 [28]
3 years ago
14

Which of the following can be characterized as a physical change?

Chemistry
1 answer:
Taya2010 [7]3 years ago
7 0

Answer:

D. Sweat evaporates from your skin

Explanation:

A physical change is a reversible process, no new substance is formed. A physical change does not affect the chemical composition of a substance.

Sweat evaporation from the skin is a physical change, because the change that occur is merely a change of state, Liquid to Gaseous state, no new substance is formed.

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During the recharge of the lead storage battery, the chemical reaction that occurs is A.)nonspontaneous.
Paha777 [63]
The chemical reaction that occurs is spontaneous. By the time the battery will recharge the cycle lead sulfate (sulfation) starts to reconvert into sulfuric acid and also with lead. Also, during the reviving procedure as power courses through the water part of the electrolyte and water, (H2O) is changed over into its unique components, hydrogen, and oxygen.
4 0
3 years ago
Amoxicillin Suspension 125 mg/ 5 ml is 125 mg of Amoxicillin per 5 ml of suspension is an example of weight to ________.
kkurt [141]

Answer : Amoxicillin Suspension 125 mg/ 5 ml is 125 mg of Amoxicillin per 5 ml of suspension is an example of weight to volume.

Explanation :

Weight by volume (w/v) means that the mass of solute present in 100 mL volume of solution.

Weight by weight (w/w) means that the mass of solute present in 100 gram of solution.

Volume by volume (v/v) means that the volume of solute present in 100 mL volume of solution.

As per question, amoxicillin suspension is, 125 mg/ 5 ml that means 125 mg of Amoxicillin present in 5 mL of suspension. So, it is an example of weight to volume.

Hence, it is an example of weight to volume.

8 0
3 years ago
What substance is neither an acid nor a base? How does it stay neutral? HURRY PLS
andreyandreev [35.5K]

Answer:

21. Most metals are brittle.

22. increases from top to bottom within the group

23. Neon is the most stable element because its highest occupied energy level is filled.

24. transfer of electrons

25. electrons are not shared equally between atoms

26. BeCl2

27. double-replacement and decomposition

28. exothermic

29. The reaction rate decreases.

30. The salt dissolved most quickly in the warm water.

31. saturated

32. feels slippery

33. hydroxide ions in solution

34. stay about the same

35-40. I do not know.

41. a bee hovering around a bee hive

42. the number of valence electrons in atoms of the element

Explanation:

21. Metals are ductile and malleable (conveniently also characteristics for chewing gum). They are stretchy and squishy. Brittle is the opposite of stretchy and squishy, and is a characteristic of non-metals.

22. On the periodic table, elements higher up are safer to use in labs. They are safer because they are less likely to react with other substances. Therefore the tendency to react with other substances increases from top to bottom within the group.

23. "Noble gases stable" (periodic table song by ASAP Science). Neon is a noble gas, therefore it is stable. When elements have only one electron to gain or lose, they are very reactive or least stable.

24. The formation of an ionic bond (metal + non-metal) is caused by the giving and receiving of electrons. Neutrons and protons do not transfer. Electrons are shared in covalent/molecular bonds (between non-metals).

25. A polar covalent bond occurs between non-metals, therefore they share electrons (ionic bonds transfer electrons). Non-metals become anions (whereas metals become cations). Polar bonds have unequal sharing and nonpolar bonds have equal sharing.

26. A one-to-two ratio of  beryllium ions to chloride ions means for every Be, there are two Cl. The number of atoms is represented by the ratio, and the numbers of atoms are written as subscripts after the element symbol.

27. MgCO2  reacting with HNO3  to form magnesium nitrate and carbonic acid is a double-replacement reaction. The elements in the beginning substances "switch partners" to form the products.

Carbonic acid then breaks down into water and carbon dioxide is decomposition. This occurs when the elements that make up a compound are split up.

28. In 2Cu + O2  => 2CuO + 315 kJ , the energy is on the right side. The right side is the products, or the stuff that was made. kJ is a unit to measure energy, therefore energy was made. Exothermic is the term that means energy was released.

29. Since oxygen is needed for a fire to burn, decreasing the oxygen slows the reaction rate (the reaction is burning, formally known as combustion).

30. Two things help substances dissolve: heat and stirring. Warm water is hotter than room-temperature water and ice water. This makes the salt dissolve faster.

31. A solution that contains more solute than it would normally hold is saturated. Saturated means there is a more than concentrated amount of solute in the solution. Concentrated is when there is a maximum amount of solute that will dissolve.

32. Acids do not feel slippery -- that is a characteristic of a base. To remember, bases are generally soaps and soaps are slippery. Acids taste sour  and bases taste bitter. Both acids and bases change the color of an indicator .

33. A base produces hydroxide ions, represented by OH. The OH is usually at the end of the chemical formula. Acids produce hydrogen ions, generally written at the front of the chemical formula.

34. Adding a little bit of acid to a buffer will cause the pH of the solution to stay about the same, probably increase a little. Buffer solutions are meant to make the pH "buffer". To remember, DVDs used to buffer. It's the same thing as "lag" for phones.

35-40: I'm sorry, I have no answer.

41. Electrons orbit like the plants revolve around the sun. Electrons revolve around a nucleus. A bee hovering around a bee hive  is probably flying around it in circles.

42. The tendency of an element to react is closely related to the number of valence electrons in atoms of the element.  If the valency is 8, the electron shell is full. The element is stable, opposite to reactive -- this applies to all noble gases (group 8A on the periodic table). If the valency is 1 or 7, the element is very close to being stable but not, the "desire" is so great and makes the element very reactive.

4 0
3 years ago
Read 2 more answers
Explain why a luminous flame of a Bunsen burner produces bright yellow light​
telo118 [61]

Answer:

because of the small soot particles

4 0
2 years ago
Read 2 more answers
Element X consist of two isotopes with masses of 62.9 and 64.9. The relative atomic mass of the element is 63.6. What is th
koban [17]

Answer:

it is 50%

Explanation:

62.9x50=3145

64.9x50=3245

3245+3145=6390

6390/100=63.9

4 0
2 years ago
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