The atom with 69 neutrons and 50 protons has a mass number of

ddd [48]

This means a release of free energy from the system corresponds to a negative change in free energy, but to a positive change for the surroundings.

3 0

3 years ago

The diagram below is an artist’s impression of a single atom of element Be. The neutrons are shown with stripes, the protons are

Ahat [919]

Answer is: beryllium-10.

The diagram shows that atom has 4 protons, 5 neutrons and 2 valence electrons.

Atomic number is the number of protons, which is characteristic of a chemical element, beryllium (Be) is an element with atomic number 4.

Two valence electrons means that atom is from 2. group of periodic table, only beryllium is from that group; sodium (1. group), boron (13. group) and carbon (14. group).

Beryllium-10 has 6 neutrons, so it is isotope (different number of neutrons or mass number).

3 0

3 years ago

Read 2 more answers

Debido a que propiedad un cuerpo flota en el agua y otro no

Nata [24]

Answer:

cuerpo flota o se hunde es su densidad con respecto a la del líquido en que se sumerge. En cambio, una nuez (densidad = 0.5) flotara en ambos líquidos mientras que una piedra (densidad = 2) se hundirá.

Explanation:

:)

8 0

3 years ago

Which of the following acids is the WEAKEST? The acid is followed by its Ka value.HF, 3.5 × 10^-4HNO2, 4.6 × 10^-4HCN, 4.9 × 10^

Mila [183]

Answer:

HCN

Explanation:

There are several factors that can tell us when an acid is stronger than another, which are the following:

1. The Polarity of the X - H Bond

2. Size of the X atom.

3. Charge on the acid.

4. Oxidation state of the central atom

5. Values of Ka and pKa.

From all of this factors, we can see that the exercise is already giving us values of Ka, and also we have different types of acid, not only with the form H - X

So, we will base the force of an acid by it's pKa value.

The pKa value which is calculated with the expression:

pKa = -logKa

pKa is a value that indicates how strong is the acid you are working with. This value can vary depending on factors such the charge of the acid. I f this charge can be easily distributed in resonance structures, the compound is more acidic, and therefore the pKa value is lower.

The lower the pKa, the more acidic the compound is.

So calculating the pKa on every structure we have:

HF: pKa = -log(3.5x10^-4) = 3.46

HNO2: pKa = -log(4.6x10^-4) = 3.34

HCN: pKa = -log(4.9x10^-10) = 9.31

HCOOH: pKa = -log(1.8x10^-4) = 3.74

HClO2: -log(1.1x10^-2) = 1.96

So according to all this values, we can conclude that the weakest acid is the HCN

4 0

3 years ago

Seaweed attached to rocks in the ocean performs photosynthesis underwater. Which statement best explains how some seaweed can su

tia_tia [17]

Answer:

It can use a small amount of sunlight for photosynthesis

Explanation:

Seaweeds are a group of marine plants/algae that grow attached to rocks underwater. However, despite their depth underwater, they still perform photosynthesis, which is a process that requires energy from sunlight.

Seaweeds are able to perform photosynthesis underwater because they are efficient users of sunlight energy. Hence, they require only a small amount of sunlight that penetrates the ocean to perform photosynthesis.

8 0

3 years ago