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enyata [817]
3 years ago
9

9.(02.02 MC)

Chemistry
2 answers:
TiliK225 [7]3 years ago
8 0

Answer:

Example A describes a physical change and Example B describes a chemical change.

Explanation:

den301095 [7]3 years ago
4 0

Answer:

Example A describes a physical change and Example B describes a chemical change.

Explanation:

Physical Change                                                                                              

The changes that occur only due to change in shape or physical properties but their chemical or internal composition remain unchanged.  

These changes were reversible.

They have same chemical property.

These changes can be observed with naked eye.

Example :

Vegetables are chopped and converted into smaller pieces the composition remain same. It is physical change.

Water converting to Ice

Water converting to gas

In this water molecule remain the same only they rearrange themselves that change its state of mater not composition

Chemical change:

The changes, that occur due to change in the composition of a substance and result in a different compound is known as chemical change.

These changes are irreversible

These changes occur due to chemical reactions

These may not be observed with naked eye

Example:

Combustion of fuel or wood: that oil or wood convert into energy, CO2 and ash in case of wood

Boiling of egg: that change the chemical composition of protein in the egg .

Food is broken up into simpler form during digestion and convert into the energy and particles which are different from original compound .

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0.352 g sample of a diprotic acid is dissolved in water and titrated with 0.150 M NaOH.0.150 M NaOH. What is the molar mass of t
Aliun [14]
<h3>Answer:</h3>

128.94 g/mol

<h3>Explanation:</h3>

Given;

Mass of diprotic acid, H₂X =0.352 g

Molarity of NaOH = 0.150 M

Volume of the NaOH = 36.4 mL

We are required to calculate the molar mass of the acid.

Note: A diprotic acid is an acid that contains 2 replaceable hydrogen atoms

<h3>Step 1: Write the balanced equation fro the reaction;</h3>

The balanced equation for the reaction between the diprotic acid and NaOH will be;

H₂X(aq) + 2NaOH(aq) → Na₂X(aq) + 2H₂O(l)

<h3>Step 2: Determine the number of moles of NaOH used </h3>

Given the molarity and volume of NaOH we can calculate the number of moles;

Moles of NaOH = Molarity × Volume

                          = 0.150 M × 0.0364 L

                         = 0.00546 moles

<h3>Step 3: Use the mole ratio to determine moles of the acid </h3>

From the equation;

1 mole of the acid reacts with 2 moles of NaOH

Therefore; H₂x : NaOH = 1 : 2

Moles of H₂x = 0.00546 moles ÷ 2

                      = 0.00273 moles

<h3>Step 4: Determine the molar mass of the acid.</h3>

Molar mass is the mass equivalent to 1 mole of a compound or element

From our calculations;

0.00273 moles = 0.352 g of the acid;

Therefore, mass in 1 mole ;

= 0.352 g ÷ 0.00273 moles

= 128.94 g/mol

Thus, the molar mass of the diprotic, H₂X is 128.94 g/mol

7 0
3 years ago
Selenium (Se) has 30 protons and 20 neutrons in each atom, therefore its atomic
allochka39001 [22]

Answer:

30, 50

Explanation:

Hello,

In this since an element's atomic number is equal to the number of protons in its atom, we can infer that selenium's atomic number is 30. Moreover, due to the fact the the neutrons are equal to the atomic mass minus the atomic number or the number of protons, by knowing the number of neutrons we compute the atomic as follows:

neutrons=mass-protons\\\\mass=neutrons+protons\\\\mass=30+20\\\\mass=50a.m.u

Thus, answer is 30, 50.

Best regards.

8 0
3 years ago
One of the basic building blocks of matter, which cannot be broken down by chemical means is a(n)______ , of which there are 92
Nadusha1986 [10]

One of the basic building blocks of matter, which cannot be broken down by chemical means is an element.

The first chemical element is hydrogen (atomic number is 1) and the last is oganesson (atomic number is 118).

Elements are scheduled in Periodic table, ordered by their atomic number.

Other example, krypton is a chemical element with symbol Kr and atomic number 36.

Krypton has 36 electron and 36. It is noble gas (group 18).

Noble gases are in group 18: helium (He), neon (Ne), argon (Ar), krypton (Kr), xenon (Xe) and radon (Rn). They have very low chemical reactivity.

More about chemical element: brainly.com/question/28376204

#SPJ4

6 0
2 years ago
Which is the correct formula for phosphorus pentachloride?
klio [65]

PCl5

hope this helps

have a wonderful day

5 0
3 years ago
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Is kingdom more specific taxon than family?
Eva8 [605]
Yes the kingdom is more specific
5 0
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