CHEMISTRY HIGH SCHOOL

Sort the following situations into chemical change or physical change:1. salt dissolves in water
2. Hydrochloric acid reacts with magnesium to produce hydrogen gas
3. a piece of copper is cut in half
4. a sugar cube is ground up
5. water is heated and changed to steam
6. iron rusts
7. ethyl alcohol evaporates
8. ice melts
9. milk sours
10. sugar dissolves in water
11. sodium and potassium react violently with water
12. pancakes cook on a griddle
13. grass grows on a lawn
14. a tire is inflated with air
15. food is digested in the stomach
16. water is absorbed by a paper towel
17. ethyl alcohol boils at 79 egress Celsius
18. paper burns
19. water freezes at 0 degrees Celsius
20. fireworks explode
21. alka-seltzer gives off carbon dioxide when added to water
22. clouds form in the sky

Answers

Answer 1
Answer: Chemical
2. Hydrochloric acid reacts with magnesium to produce hydrogen gas
5. water is heated and changed to steam
6. iron rusts
9. milk sours
7. ethyl alcohol evaporates
11. sodium and potassium react violently with water
12. pancakes cook on a griddle
15. food is digested in the stomach
17. ethyl alcohol boils at 79 egress Celsius
18. paper burns
20. fireworks explode
21. alka-seltzer gives off carbon dioxide when added to water
22. clouds form in the sky

Physical
19. water freezes at 0 degrees Celsius
16. water is absorbed by a paper towel
14. a tire is inflated with air 
13. grass grows on a lawn
1. salt dissolves in water
3. a piece of copper is cut in half
4. a sugar cube is ground up
8. ice melts
10. sugar dissolves in water

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The modern atomic model is also sometimes called the __________ model.a. solar system
b. Bohr
c. plum pudding
d. quantum mechanics

Answers

The correct answer is B. The modern atomic model is also sometimes called the Bohr model. This model was introduced by Niels Bohr in 1913. According to this model, an atom is a small, positively charged nucleus which is surrounded by negatively charged particles called electrons.

The answer is B. Bohr

The absorption of some minerals is regulated by being bound to _____. A) Fats B) Starches C) Transport proteins D) Amino acids

Answers

Answer is  C) Transport proteins

Which of the following is a balanced equation for cellular respiration? A.C6H12O6 + 6O2 6CO2 + 6H2O
B.CO2 + H2O C6H12O6 + O2
C.6CO2 + 6H2O C6H12O6 + 6O2
D.6C6H12O6 + 6O2 6CO2 + H2O
E.C6H12O6 + O2 CO2 + H2O
F.6CO2 + 6H2O C6H12O6 + 6O2

Answers

I did all of the work, and F is the answer I ended up with

The lewis structure of n2h2 shows __________.a.a nitrogen-nitrogen triple bond
b.a nitrogen-nitrogen single bond
c.each nitrogen has one nonbinding electron pair
d.each nitrogen has two nonbinding electron pairs
e.each hydrogen has one nonbonding electron pair

Answers

The Lewis structure of Diimide (N₂H₂) is shown below.

In this molecule two Nitrogen atoms attached to each other through a double bond are further attached to one one Hydrogen atom. Also, each Nitrogen atom carries one non-binding electron pair (Lone Pair) (Highlighted RED).

Result:
          Option-C (each nitrogen has one nonbinding electron pair) is the correct answer.

The lewis structure of n2h2 shows

c. each nitrogen has one nonbinding electron pair

Lewis structures are diagrams that show the bonds between the atoms of a molecule and the lone pair of electrons that might exist in a molecule.

Further Explanation

Lewis structures can be drawn for each covalently bonded molecule, as well as coordination compounds. The Lewis structure is named after Gilbert N. Lewis, who introduced in his 1916 article The Atom and the Molecule. The Lewis structure extends the concept of the electron point diagram by adding lines between atoms to represent pairs together in chemical bonds.

The Lewis structure shows each atom and its position in the molecular structure using its chemical symbol. Lines are drawn between atoms that are bound to one another (pairs of dots can be used instead of lines). The excess electrons that make up lonely pairs are represented as pairs of points and are placed next to the atom.

The number of electrons represented in the Lewis structure is equal to the number of valence electrons in each atom. Non-valence electrons are not represented in the Lewis structure.

In the case of Lewis structures, formal charges are used in the description, comparison, and assessment of the topological and resonant structures that might occur by determining the apparent electron charge of each atom, based on the structure of the electron points, assuming exclusive covalence or non-polar bonds. Formal charges have been used in determining possible electron reconfigurations when referring to reaction mechanisms, and often produce the same sign as the partial charge of atoms, with the exception.

Learn More

Lewis structures brainly.com/question/9736616

Atom/Electron brainly.com/question/9736616

Details

Class: High School

Subject: Chemistry

Keyword: lewis, Structure, electron

Which of the following is considered to be a dangerous procedure in the laboratory setting? a. Pouring all liquids, especially acids and bases, over the sink
b. Wearing goggles
c. Pushing glass tubing, thermometers, or glass thistle tubes through a rubber cork
d. Pointing the mouth of a test tube that is being heated away from you and others
e. Knowing where the fire extinguisher and eyewash stations are located

Answers

The answer is (A) , because all other options are safety precautions, not dangerous.
I think it's c because a is good as it won't cause spills on the floor, b you must do for eye safety d) is also for safety so chemicals don't burn or spit at you And e is needed incase a fire occurs or something is in your eye and immediately needs washing out therefore c is the only one which could be a danger

If an atom has 3 protons, what is its atomic number?

Answers

Answer:

Atomic Number = 3.

Explanation:

The number of protons determines the atomic number. Basically the number of protons is the exact same as the atomic number.

Protons 3 = Atomic number 3
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