All categories

3 years ago

10 points !! Which can happen during a physical change?

1 answer:

5 0

I think that the answer is A because if you think about water for an example. When water turns into ice, it's still technically water, just the molecules are frozen. The water is physically changed. It could also see why you think it is B but I don't think so completely. It doesn't really make sense to me. So I'd choose A. It's definitely not C or D.

You might be interested in

In the laboratory, a general chemistry student measured the pH of a 0.529 M aqueous solution of phenol (a weak acid), C6H5OH to

Artyom0805 [142]

Answer:

The dissociation constant of phenol from given information is $9.34\times 10^{-11}$ .

Explanation:

The measured pH of the solution = 5.153

$C_6H_5OH\rightarrow C_6H_5O^-+H^+$

Initially c

At eq'm c-x x x

The expression of dissociation constant is given as:

$K_a=\frac{[C_6H_5O^-][H^+]}{[C_6H_5OOH]}$

Concentration of phenoxide ions and hydrogen ions are equal to x.

$pH=-\log[x]$

$5.153=-\log[x]$

$x=7.03\times 10^{-6} M$

$K_a=\frac{x\times x}{(c-x)}=\frac{x^2}{(c-x)}=\frac{(7.03\times 10^{-6} M)^2}{ 0.529 M-7.03\times 10^{-6} M}$

$K_a=9.34\times 10^{-11}$

The dissociation constant of phenol from given information is $9.34\times 10^{-11}$ .

4 0

3 years ago

If one were asked to choose between paper or plastic which would be chosen and which one would benefit the environment?

vekshin1

It would be plastic Becaus we can recreate things with plastic and other things that are recyclable. Since,we mostly cut down trees everyday for paper,not knowing that we are wasting natural resources, and destroying animal homes and food.

6 0

4 years ago

1. Find the number of protons, neutrons, electrons and electronic structure of flourine 919F.

77julia77 [94]

1. ₉¹⁹F

2. Mg(OH)₂

3. 2H₂ + O₂ ⇒ 2H₂O

<h3>Further explanation</h3>

1. Fluorine, atomic number : 9 , mass number = 19

Symbol : ₉¹⁹F

protons=electrons=atomic number = 9

neutrons = mass number - atomic mass

$\tt n=19-9=10$

Configuration : [He] 2s² 2p⁵

2. Magnesium hydroxide is an ionic compound and is a strong base consisting of 2 ions:

Positive ion: Magnesium: Mg²⁺

negative ion: Hydroxide: OH⁻

The charges of the two are crossed, so that the compound becomes:

Mg(OH)₂

3. Reaction :

H₂ + O₂ --------> H₂O

give coefficient :

aH₂ + bO₂ --------> H₂O

H, left = 2a, right 2⇒2a=2⇒a=1

O, left = 2b, right 1⇒2b=1⇒b=0.5

Reaction becomes :

H₂ + 0.5O₂ --------> H₂O x 2

2H₂ + O₂ --------> 2H₂O

4 0

3 years ago

Give two reasons why mixing and heating sulphur powder and iron filings on a watch glass is chemical change

Nadusha1986 [10]

Answer:

When iron filings and sulphur powder are mixed and heated they undergo a chemical reaction and form ferrous sulphide (FeS). It is a new substance which has properties entirely different from Fe and S. Therefore, heating of mixture of iron and sulphur powder is a chemical change.

7 0

3 years ago

Explain how the burning of fossil fuels can cause a disruption to the carbon cycle.

TiliK225 [7]

By adding a lot of carbon dioxide of what is necessary could be harmful for living things, the carbon cycle is something natural, this cycle released enough carbon dioxide, as result not to damage living things so by adding more could prejudicial

8 0

3 years ago

Read 2 more answers