Identify the following reaction type using the chemical equation below*

What is the difference between chemical change and physical change

Nadusha1986 [10]

In a physical change the appearance or form of the matter changes but the kind of matter in the substance does not. However in a chemical change, the kind of matter changes and at least one new substance with new properties is formed. Hope this helps!

7 0

2 years ago

This is science

irakobra [83]

Answer:

a= seismic waves I think

b= outer

c= crust I think

6 0

2 years ago

Justin mixed two clear liquids together during an experiment and made the following observations:

svp [43]

Answer:

B. A chemical change occurred which caused the liquid's physical properties to change.

Explanation:

The reduction of the temperature of the system meant that the reaction absorbed heat energy from it. This shows that a chemical reaction was in progress. New products were formed, and this is proved by the change in the color to blue.

6 0

2 years ago

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What is the pOH of a 0.150 M solution of potassium nitrite? (Ka HNO2 = 4.5 x 10−4 )

yanalaym [24]

Answer:

11.9 is the pOH of a 0.150 M solution of potassium nitrite.

Explanation:

Solution : Given,

Concentration (c) = 0.150 M

Acid dissociation constant = $k_a=4.5\times 10^{-4}$

The equilibrium reaction for dissociation of $HNO_2$ (weak acid) is,

$HNO_2+H_2O\rightleftharpoons NO_2^-+H_3O^+$

initially conc. c 0 0

At eqm. $c(1-\alpha)$ $c\alpha$ $c\alpha$

First we have to calculate the concentration of value of dissociation constant $(\alpha )$ .

Formula used :

$k_a=\frac{(c\alpha)(c\alpha)}{c(1-\alpha)}$

Now put all the given values in this formula ,we get the value of dissociation constant $(\alpha )$ .

$4.5\times 10^{-4}=\frac{(0.150\alpha)(0.150\alpha)}{0.150(1-\alpha)}$

$4.5\times 10^{-4} - 4.5\times 10^{-4}\alpha =0.150\alpha ^2$

$0.150\alpha ^2+4.5\times 10^{-4}\alpha-4.5\times 10^{-4}=0$

By solving the terms, we get

$\alpha=0.0533$

No we have to calculate the concentration of hydronium ion or hydrogen ion.

$[H^+]=c\alpha=0.150\times 0.0533=0.007995 M$

Now we have to calculate the pH.

$pH=-\log [H^+]$

$pH=-\log (0.007995 M)$

$pH=2.097\approx 2.1$

pH + pOH = 14

pOH =14 -2.1 = 11.9

Therefore, the pOH of the solution is 11.9

4 0

3 years ago

Match the following aqueous solutions with the appropriate letter.

Alla [95]

Answer:

Explanation:

When a salt is dissolved , it increases the boiling point . Increase in boiling point depends upon number of ions . So it is a colligative property .

.19 m AgNO₃ . Each molecule will ionize into two ions . So effective molar concentration is 0.19 x 2 = .38 m

0.17 m CrSO4.Each molecule will ionize into two ions . So effective molar concentration is 0.17 x 2 = .34 m

0.13 m Mn(NO₃)₂. Each molecule will ionize into three ions . So effective molar concentration is 0.13 x 3 = .39 m

0.31 m Sucrose(nonelectrolyte). Molecules will not ionize . So effective molar concentration is 0.31 x 1 = .31 m

Higher the molar concentration , greater the depression in boiling point .

So lowest boiling point is 0.13 m Mn(NO₃)₂.

second highest boiling point is 0.19 m AgNO3.

Third lowest boiling point is 0.17 m CrSO4

Highest boiling point or lowest depression 0.31 m Sucrose.

a . 4

b . 1

c . 2

d . 3

6 0

2 years ago