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azamat
3 years ago
5

Sharpening a pencil leaves behind pencil shavings. is sharpening a physical or chemical change

Chemistry
2 answers:
marta [7]3 years ago
7 0
Physical

because the pencil is not changing to a new substance, just changing form :)
IgorLugansk [536]3 years ago
6 0
Physical damage. 

If you burned the pencil, it would be considered chemical. 
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PLEASE HELP!!!!!!!!Which of the following chemical reactions is best clasified as an acid-base reaction?
ANTONII [103]

Answer:

d . H₂SO₄ + 2KOH → K₂SO₄ + 2H₂O

Explanation:

  • The given reactions are:

a . 2HgO → 2Hg + O₂,

It is a decomposition reaction, that HgO is decomposed to give Hg and O.

b . Na₂SO₄ + BaCl₂ → BaSO₄ + 2NaCl,

It is a double replacement reaction where two salts replaces their cations and anions with each others producing 2 new salts.

c . Zn + 2AgNO₃ → Zn(NO₃)₂ + 2Ag,

It is a single replacement reaction, that Zn replaces Ag from its salt.

d . H₂SO₄ + 2KOH → K₂SO₄ + 2H₂O

It is acid-base reaction "neutralization reaction" where H₂SO₄ (acid) reacts with KOH (base) producing K₂SO₄ (salt) and water.

  • So, the right choice is:

<em>d . H₂SO₄ + 2KOH → K₂SO₄ + 2H₂O</em>

<em></em>

3 0
4 years ago
the bohr model is an inaccurate model of the atom because there is no way to measure the exact of an electron in an atom
Liono4ka [1.6K]
The Bohr model is an inaccurate model because there is no way to measure the exact position or location of an electron in an atom.
5 0
3 years ago
The formation of nitryl fluoride, 2no2(g)+f2(g)⇌2no2f(g) is first order in no2 and first order in f2. if the concentration of no
ra1l [238]
The reaction is:

2 NO₂ (g) + F₂ (g) ⇆  2 NO₂F (g)

The stoichiometric coefficients of the substances balance out each other to obey the Law of Definite Proportions. Now, you have to note that determining the reaction rate expression is specific to a certain type of reaction. So, this are determined empirically through doing experiments. But in chemical reaction engineering, to make things simple, you assume that the reaction is elementary. This means that the order of a reaction with respect to a certain substance follows their individual stoichiometric coefficients. What I'm saying is, the stoichiometric coefficients are the basis of our reaction rate orders. For this reaction, the rate order is 2 for NO₂, 1 for F₂ and 2 for NO₂F. When the forward and reverse reactions are in equilibrium, then it applies that:

Reaction rate of disappearance of reactants = Reaction rate of formation of products.

Therefore, we can have two reaction rate constants for this. But since the conditions manipulated are the reactant side, let's find the expression for reaction rate of disappearance of reactants.

-r = k[NO₂]²[F₂]

The negative sign before r signifies the rate of disappearance. If it were in terms of the product, that would have been positive. The term k denotes for the reaction rate constant. That is also empirical. As you can notice the stoichiometric coefficients are exponents of the concentrations of the reactants. Let's say initially, there are 1 M of NO₂ and 1 M of F₂. Then,

-r = k(1)²(1)
-r = k

Now, if we change 1 M of NO₂ by increasing it to its half, it would now be 1.5 M NO₂. Then, if we quadruple the concentration of F₂, that would be 4 M F₂. Substituting the values:

-r = k(1.5)²(4)
-r = 9k

So, as you can see the reaction rate increase by a factor of 9.
4 0
4 years ago
Classify each statement as a property of ethers, alcohols, or both ethers and alcohols?
natita [175]

Explanation:

1. Only alcohols forms hydrogen bond  between themselves and with other compounds containing an O-H, N-H, or F-H bond, such as water.

2. Alcohols up to 4 carbons are miscible in water because they have hydrogen bonded to oxygen and can form hydrogen bond with water. However, it is not possible for ethers.

3. When comparing ethers and alcohols of similar molecular weights, ethers have lower boiling point than alcohol. This is because of the presence of hydrogen bond in alcohols.

8 0
3 years ago
X(OH)2 + 2HCl XCl2 +2H2O
lesya692 [45]

Answer:

dont cheat guys

8 0
3 years ago
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