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Chemistry

2 answers:

svlad2 [7]3 years ago

6 0

The heavy particles all passed straight through the foil, because the atoms are mostly empty space.

Answer is third choice

eimsori [14]3 years ago

6 0

Answer: Some of the heavy particles bounced off the foil, because there is a dense, positive area in the atom.

Explanation:

In Rutherford's experiment, he took a gold foil and bombarded it with alpha particles which carry positive charge. He thought that the alpha particles will pass straight through the foil, but to his surprise, many of them passed through, some of them deflected their path and a few of them bounced back.

From this he concluded that in an atom, there exist a small positive charge in the center. Due to this positive charge, the alpha particles deflected their path and some of them bounced straight back their path.

Thus he concluded that there is a dense, positive area in the atom.

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Write the charge balance for a solution that contains h , oh–, mg2 , hso4–, so42–, mg(hso4) , mg(oh) , na , and no3–.

Olenka [21]

A solution is when a solute is added to a water solvent. Since water is neutral, the charge of the said solution is dictated by the charge of the ion. This is the subscript of the element. If it is not stated, then we use the common ion form.

1. H: The charge for hydrogen ion is +1.
2. OH⁻: The charge is ⁻1.
3. Mg2: This ion has a charge of +2.
4. HSO₄⁻: -1
5. SO₄²⁻: -2
6. Mg(HSO₄): This is not an ion, but an undissociated compound. So, it has a neutral charge of 7.
7. Mg(OH): Neutral at pH 7
8. Na: Sodium ion has a charge of +1.
9. NO₃⁻: -1.

5 0

3 years ago

(1.) Using Beer's Law, How will the absorbance measured for the solutions change as the concentration of aspirin in solutions in

Vesnalui [34]

Answer:

(1) The absorbance of the aspirin in solutions will increase.

(2) [ASA]f = 3.79x10⁻⁴M

(3) [ASA]i = 3.79x10⁻³M

(4) m ASA = 0.171g

Explanation:

The Beer's Law is expressed by:

$A = \epsilon \cdot l \cdot C$ (1)

where A: is the absorbance of the species, ε: is the molar attenuation coefficient, l: is the pathlength and C: is the concentration of the species

(1) From equation (1), the relation between the absorbance of the species and its concentration is directly proportional, so if the aspirin concentration in solutions increases, the absorbance of the solutions will also increase.

(2) Starting in the given expression for the relationship between absorbance and concentration of ASA, we can calculate its concentration in the solution:

$A = 1061.5 \cdot [ASA]$

$[ASA] = \frac{A}{1061.5} = 3.79 \cdot 10^{-4}M$

Therefore, the aspirin concentration in the solution is 3.79x10⁻⁴ M

(3) To calculate the stock solution concentration, we can use the next equation:

$V_{i} [ASA]_{i} = V_{f} [ASA]_{f}$

where Vi: is the stock solution volume=10mL, Vf: is the solution diluted volume=100mL, [ASA]i: is the aspirin concentration of the stock solution and [ASA]f: is the aspirin concentration of the diluted solution

$[ASA]_{i} = \frac{V_{f} \cdot [ASA]_{f}}{V_{i}} = \frac {100mL \cdot 3.79\cdot 10^{-4} M}{10mL} = 3.79 \cdot 10^{-3} M$

Hence, the concentration of the stock solution is 3.79x10⁻³M

(4) To determine the aspirin mass in the tablet, we need to use the following equation:

$m_{ASA} = \eta_{ASA} \cdot M_{ASA} = [ASA]_{i} \cdot V_{0} \cdot M_{ASA}$

where η: is the aspirin moles = [ASA]i V₀, M: is the molar mass of aspirin=180.158g/mol, V₀: is the volume of the volumetric flask=250mL and [ASA]i: is the aspirin concentration in the volumetric flask which is equal to the stock solution=3.79x10⁻³M

$m_{ASA} = 3.79 \cdot 10^{-3} \frac{mol}{L} \cdot 0.250L \cdot 180.158 \frac{g}{mol} = 0.171 g$