Who hypothesized that electrons orbit around a nucleus? Bohr Greek philosophers Thomson Dalton

Which statements describe dark matter? Check all that apply. It is invisible. It is the same as dark energy. It is well understo

Alla [95]

Dark matter is invisible and does not emit electromagnetic radiation. Dark matter is part of a theory that hypothesis the existence of a counterpart to the particles we know in physics, in order to balance the universe that otherwise would be largely unbalanced right now. However, the theory right now is not yet proven.

4 0

3 years ago

Read 2 more answers

I'm trying to do question number 2.56

Lunna [17]

The answer is in the picture which is given below:

8 0

3 years ago

The reaction 2a + b --> c + d has an activation energy of 80.0 kj/mol. at 320°c, the rate constant k = 1.80 x 10-2 l mol-1 s-

Naddik [55]

To determine the k for the second condition, we use the Arrhenius equation which relates the rates of reaction at different temperatures. We do as follows:

ln k1/k2 = E / R (1/T2 - 1/T1) where E is the activation energy and R universal gas constant.

ln 1.80x10^-2 / k2 = 80000 / 8.314 ( 1/723.15 - 1/593.15)

k2 = 0.3325 L / mol-s

5 0

4 years ago

Acidity is a measure of the amount of dissolved hydroxide ions in a solution.

Gekata [30.6K]

The concentration of hydrogen ions in a solution is a measure of its acidity. So the correct option is (b) false.

When an Arrhenius acid is dissolved in water, hydrogen ions are produced:

H+(aq) + A- = HA + H2O (aq)

Here, H+ is the hydrogen cation, A- is the solvated anion, also known as the conjugate base, and HA is the non-dissociated acid. When an Arrhenius base is dissolved in water, hydroxide ions are produced:

BOH + H2O → B+(aq) + OH-(aq)

Is a material with at least one hydrogen atom that has the ability to split apart in an aqueous solution to produce an anion and an H + ion (a proton), creating an acidic solution. Bases are substances that, when dissolved in water, create hydroxide ions (OH) and a cation, resulting in a basic solution.

Learn more about hydrogen here:

brainly.com/question/16979348

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4 0

2 years ago

The successive ionization energies for a given element are listed. How many valence electrons does it have?

damaskus [11]

Answer:

3 valence electrons

Explanation:

Let us first find the amount increased for everything.

From 1st to 2nd, 1048 - 620 = 428

428 increased from 1st to 2nd.

From 2nd to 3d, 2144 - 1048 = 1096

1096 increased from 2nd to 3rd.

From 3rd to 4th, 8724 - 2144 = 6580

6580 increased from 3rd to 4th.

From 4th to 5th, 10141 - 8724 = 1417

From 3rd to 4th, it increased the most. Therefore, we assume that those are the beginning core electrons and not valence electrons. Also, starting from 3rd, they are all core electrons.

For the 1st and 2nd, we can assume they are valence electrons because the kJ/mol didn't increase that much.

Since the core electrons started from the 3rd, we most likely have 3 valence electrons.

So the final answer is 3.

Hope it helped!

5 0

3 years ago