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Leya [2.2K]
3 years ago
12

Is this true or false ?

Chemistry
2 answers:
Natali5045456 [20]3 years ago
8 0

Answer:

False. Atom models have changed in the past centuries.

stiks02 [169]3 years ago
7 0

Answer:

false

Explanation:

The atom model has changed over time because of the discovery of subatomic particles

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Determine which compound would raise the boiling point of water the most
Olenka [21]
All of the provided salts will increase the boiling point of water due to Boiling point elevation is considered as one of the colligative properties that only affected by the number of particles present in solution regardless their nature.

All of the choices are considered as electrolytes (ionizes in water) so the one which gives higher number of ions will raise the boiling point the most so the correct answer is A) AlCl₃ due to it ionizes to give 4 ions one Al and 3 Cl while NaCl gives only 2 ions, CaCl₂ gives 3 ions and KBr gives 2 ions 

So the correct answer is A) 2.0 M AlCl₃ 
8 0
4 years ago
Please I really really need help!!!!
Zigmanuir [339]

Answer:

1) It is the number of particles in one mole of substance. It is an arbitrary definition to denote an amount of substance, not by its weight but by its number of molecules. Why? because that is convenient when doing certain calculations involving molecule formulas.

2) 1 mole of substance contains exactly as many particles as there are atoms  in 12 grams of carbon-12.

3) The unified atomic mass unit is 1/12 of the mass of 1 carbon-12 atom.

So you see all three concepts are linked together.

4 0
3 years ago
<img src="https://tex.z-dn.net/?f=H_2PO_4%5E-%28aq%29%20%5Crightarrow%20H%5E%2B%28aq%29%20%2B%20HPO_4%5E%7B2-%7D%28aq%29" id="Te
klasskru [66]

Answer:

The pH of the buffer solution = 8.05

Explanation:

Using the Henderson - Hasselbalch equation;

pH = pKa₂ + log ( [HPO₄²-]/[H₂PO4⁻]

where pKa₂ = -log (Ka₂) = -log ( 6.1 * 10⁻⁸) = 7.21

Concentration of OH⁻ added = 0.069 M (i.e. 0.069 mol/L)

[H₂PO4⁻] after addition of OH⁻ = 0.165 - 0.069 = 0.096 M

[HPO₄²-] after addition of OH⁻ = 0.594 + 0.069 = 0.663 M

Therefore,

pH = 7.21 + log (0.663 / 0.096)

pH = 7.21 + 0.84

pH = 8.05

4 0
3 years ago
What are the coefficients when the chemical equation below is balanced?
Blizzard [7]
The correct answer is D
6 0
3 years ago
a stone is found to have a volume of 34.9cm3. it has a mass of 30.8g. what is the density of the stone
FromTheMoon [43]

Answer:

Explanation:

ρ =  

m

V

=  

30.8 gram

34.9 cubic meter

=  0.88252148997135 gram/cubic meter

=  0.00088252148997135 kilogram/cubic meter

3 0
4 years ago
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