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3 years ago

Which event would be impossible to explain by using John Dalton’s model of the atom?

2 answers:

5 0

The scientist thought that the atom was the smallest particle in the universe is John Dalton. He established the atomic theory which consists of five; elements are made of extremely small particles called atoms, atoms of different element have different sizes, mass and physic – chemical properties, atoms cannot be divided further, destroyed or created, atoms can combine to form compounds and in chemical reaction, atoms can be combined, separated or rearranged.

Wittaler [7]3 years ago

3 0

Answer:

It’s A

Explanation:

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Which of the following additions to alkenes occur(s) specifically in an syn fashion?

BlackZzzverrR [31]

Answer:

E) A, B, and C

Explanation:

Syn addition refers to the addition of two substituents on the same face or side of a double bond. This differed from anti addition which a occurs across opposite face of the double bond.

Hydrogenation, hydroboration and dihydroxylation all involve syn addition to the double bond, hence the answer chosen above.

8 0

2 years ago

Why does Hess's law allow you to determine the enthalpy change of a<br> reaction?

lana [24]

Enthalpy is a state function

Explanation:

The Hess's law allows us to determine the enthalpy change of a reaction because enthalpy is a state function. It does not depend on the individual path take in going from reactants to products in the reaction.

Enthalpy changes are the heat changes accompanying physical and chemical changes.
It is the difference between the heat content of product in the final state and the reactants.
Enthalpy changes for some reactions are not easily measurable experimentally.
To calculate such heat changes, we apply the Hess's law of heat summation.
The law states that "the heat change of a reaction is the same whether it occurs in a step or several steps".
The Hess's law is simply based on the first law of thermodynamics by which we know that energy is conserved in every system.

learn more:

Hess's law brainly.com/question/11293201

#learnwithBrainly

5 0

3 years ago

Metamorphic rocks that melt in a holt fluid can recystallize into a different form of rock

kotykmax [81]

I think that type of rock is call Igneous rock because the igneous rock is molten rock from volcanoes.

7 0

2 years ago

in a simulation mercury removal from industrial wastewater, 0.020 L of 0.10 M sodium sulfide reacts with 0.050 L of 0.010 M merc

Margarita [4]

Answer: 0.1161 grams of mercury(II) sulfide) form.

Explanation:

To calculate the number of moles for given molarity, we use the equation:

$\text{Molarity of the solution}=\frac{\text{Moles of solute}\times 1000}{\text{Volume of solution (in L)}}$ .....(1)

a) Molarity of $Na_2S$ solution = 0.10 M

Volume of solution = 0.020 L

Putting values in equation 1, we get:

$0.10M=\frac{\text{Moles of }Na_2S}{0.020L}\\\\\text{Moles of Na_2S}={0.10mol/L\times 0.020}=0.002mol$

$\text {Moles of}Na_2S=0.10M\times 0.020L=0.002mol$

b) Molarity of $Hg(NO_3)_2$ solution = 0.010 M

Volume of solution = 0.050 L

Putting values in equation 1, we get:

$0.010M=\frac{\text{Moles of }Hg(NO_3)_2}{0.050L}\\\\\text{Moles of }Hg(NO_3)_2={0.010mol/L\times 0.050}=0.0005mol$

$Na_2S+Hg(NO_3)_2\rightarrow HgS+2NaNO_3$

According to stoichiometry :

1 mole of $Hg(NO_3)_2$ reacts with 1 mole of $Na_2S$

Thus 0.0005 moles of $HgNO_3$ reacts with= $\frac{1}{1}\times 0.0005=0.0005$ moles of $Hg(NO_3)_2$

Thus $Hg(NO_3)_2$ is the limiting reagent and $Na_2S$ is the excess reagent.

According to stoichiometry :

1 mole of $Hg(NO_3)_2$ forms= 1 mole of $Hg_2S$

Thus 0.0005 moles of $Hg(NO_3)_2$ forms= $\frac{1}{1}\times 0.0005=0.0005$ moles of $Hg_2S$

mass of $H_2S=moles\times {\text {Molar mass}}=0.0005mol\times 232.2g/mol=0.1161g$

Thus 0.1161 grams of mercury(II) sulfide) form.

5 0

3 years ago

Determine the percent ionization of a 0.225 M solution of benzoic acid. Express your answer using two significant figures.

Assoli18 [71]

Answer:

1.68% is ionized

Explanation:

The Ka of benzoic acid, C₇H₆O₂, is 6.46x10⁻⁵, the equilibrium in water of this acid is:

C₇H₆O₂(aq) + H₂O(l) ⇄ C₇H₅O₂⁻(aq) + H₃O⁺(aq)

Ka = 6.46x10⁻⁵ = [C₇H₅O₂⁻] [H₃O⁺] / [C₇H₆O₂]

<em>Where [] are concentrations in equilibrium</em>

In equilibrium, some 0.225M of the acid will react producing both C₇H₅O₂⁻ and H₃O⁺, the equilibrium concentrations are:

[C₇H₆O₂] = 0.225-X

[C₇H₅O₂⁻] = X

[H₃O⁺] = X

Replacing:

6.46x10⁻⁵ = [X] [X] / [0.225-X]

1.4535x10⁻⁵ - 6.46x10⁻⁵X = X²

1.4535x10⁻⁵ - 6.46x10⁻⁵X - X² = 0

Solving for X:

X = -0.0038. False solution, there is no negative concentrations.

X = 0.00378M. Right solution.

That means percent ionization (100 times Amount of benzoic acid ionized over the initial concentration of the acid) is:

0.00378M / 0.225M * 100 =

<h3>1.68% is ionized</h3>

8 0

2 years ago