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Harman [31]
4 years ago
12

Which of the following is an irreversible physical change?

Chemistry
1 answer:
Yuliya22 [10]4 years ago
3 0

Answer:

b) sharpening a pencil

Explanation:

If you melt lead, boil water, or dissolve sugar in water, you can return all of them back to their original state. If you sharpen a pencil, you can't reattach the shavings as they were originally.

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2000 joules are required to heat 125 grams of an unknown substance from 10 c to 28 c. What is the specific heat of the substance
Delicious77 [7]
Hello! Specific heat is the amount of energy required by known amount of substance to raise its temperature by one degree celsius. In our question it is given that 2000J energy when supplied to 125 g of unknown substance raised its temperature by 18 oC. So, The specific heat is calculated as follow;

3 0
3 years ago
You need 1.2 moles of H2SO4 for an experiment. You weigh out 100g of this colorless syrupy liquid. Do you have enough?
Sladkaya [172]
Answer is: not enough <span>colorless syrupy liquid.
</span>n(H₂SO₄) = 1,2 mol.
M(H₂SO₄) = 2Ar(H) + Ar(S) + 4Ar(O) · g/mol.
M(H₂SO₄) = 2·1 + 32 + 4·16 · g/mol.
M(H₂SO₄) = 98 g/mol.
m(H₂SO₄) = n(H₂SO₄) · M(H₂SO₄).
m(H₂SO₄) = 1,2 mol · 98 g/mol.
m(H₂SO₄) = 117,6 g needed.
100 g is less that 117,6 g.
8 0
4 years ago
HURRY!!<br><br><br><br><br><br><br><br><br><br><br> I NEEE HELP!!!
Ludmilka [50]

Answer:

NEEE

Explanation:

5 0
3 years ago
Predict the shape of the molecule.
GuDViN [60]

Number of electron pairs = \frac{1}{2}[V+N-C+A]

2

1

[V+N−C+A]

V = number of valence electrons present in central atom

N = number of monovalent atoms bonded to central atom

C = charge of cation

A = charge of anion

SbCl_5SbCl

5

:

In the given molecule, antimony is the central atom and there are five chlorine as monovalent atoms.

The number of electron pairs are 5 that means the hybridization will be sp^3dsp

3

B and geometry of the molecule will be trigonal bipyramidal.

6 0
2 years ago
3. How many atoms in 3.91 moles of sodium?
Gala2k [10]

Answer:

Explanation:

The formula for sodium is Na. It does not form a molecule in some way.

1 mol Na = 6.02*10^23 atoms

3.91 mol = x                                    Cross multiply

x = 3.91 * 6.02 * 10^23

x = 23.65 * 10^23

x = 2.365 * 10^24

Scientific notation is always expressed as a number 1 ≤ x < 10

3 0
3 years ago
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