if an element [x] contains 8 protons, 8 neutrons and 8 electrons, the atomic number of the element is ?

A solid rubber ball with a mass of 5.9 grams sank in water. A hollow rubber ball with the same mass floats in water. Explain why

Stells [14]

Answer:

The hollow ball is more buoyant than the solid ball.

Explanation:

The hollow ball will float while the solid ball sinks because the volume of water displaced by the hollow ball is more than that displaced by the solid ball.

An object floats when it displaces a volume of water equal to its weight. A solid ball is more compact, and hence, does not displace a lot of water when dropped into a bowl full of water. On the other hand, the hollow ball will have a larger curved surface area, since it has no fill. This will make it displace a larger volume of water and hence make it float.

4 0

3 years ago

Substance formed by the chemical combination of elements is called

nikitadnepr [17]

Answer:

chemical equation

Explanation:

3 0

3 years ago

Mercury is the only metal that is a liquid at room temperature. When mercury vapor is inhaled, it is readily absorbed by the lun

Lapatulllka [165]

Answer:

P = 0.0166 mm Hg

Explanation:

To solve this question, we need to use the Clausius Clapeyron equation, which is a commonly used expression to calculate vapour pressure at a given temperature. We have the enthalpy of vaporization of the mercury, so, let's write the equation:

Clausius Clapeyron equation:

Ln (P₂ / P₁) = (-ΔHv / R)(1/T₂ - 1/T₁) (1)

Where:

R: universal constant of gases (8.314 J / K.mol)

P₂: Vapour pressure at 43°C (or 316 K)

P₁: Pressure of mercury at the boiling point (1 atm)

T₂: temperature at 43 °C

T₁: Boiling point of mercury (357 °C or 630 K)

As we are given the boiling point of the mercury, we can safely assume that the pressure at this point is 1 atm, becuase remember that when a sustance boils, is because it's internal pressure has reached the atmospherical pressure of 1 atm. With this clear, all we just need to do is solve for P₂. We are going to do this very slowly so you can understand the process. First let's replace the given data:

Ln (P₂ / 1) = (-59100 J/mol / 8.314 J / K.mol) (1/316 - 1/630)

Ln P₂ = -7108.49 * (3.16x10⁻³ - 1.59x10⁻³)

Ln P₂ = -7108.49 * (1.51x10⁻³)

Ln P₂ = -10.7338

P₂ = 10⁽⁻¹⁰°⁷³³⁸⁾

P₂ = 2.18x10⁻⁵ atm

We can express this value in mm Hg and it will be:

P₂ = 2.18x10⁻⁵ * 760

Hope this helps

8 0

3 years ago

Electron affinity is the measure of the attraction of an electron toward an isolated gaseous atom. When an electron is added to

zhuklara [117]

False

Explanation:

Electron affinity is negative when energy is absorbed and it is positive when energy is released.

Electron affinity is defined as the energy released in adding an electron to a neutral atom in the gas phase.

It is a measure of the readiness of an atom to gain an electron.

In a reaction where energy is released, electron affinity is usually positive. These reactions are called exothermic reactions.

Endothermic reactions in which energy is absorbed have negative electron affinity values.

Learn more:

Endothermic reactions brainly.com/question/12964401

#learnwithBrainly

6 0

3 years ago

In the laboratory you dissolve 13.9 g of potassium phosphatein a volumetric flask and add water to a total volume of 250mL.

tensa zangetsu [6.8K]

Answer:

Molarity of the solution? 0,262 M.

Concentration of the potassium cation? 0,786 M.

Concentration of the phosphate anion? 0,262 M.

Explanation:

Potassium phosphate (K₃PO₄; 212,27 g/mol) dissolves in water thus:

K₃PO₄ → 3 K⁺ + PO₄³⁻ <em>(1)</em>

Molarity is an unit of chemical concentration given in moles of solute (K₃PO₄) per liters of solution.

There are 250 mL of solution≡0,25 L

The moles of K₃PO₄ are:

13,9 g of K₃PO₄ × $\frac{1mol}{212,27 g}$ = 0,0655 moles of K₃PO₄

The molarity of the solution is:

$\frac{0,0655 moles}{0,25L}$ = 0,262 M

In (1) you can see that 1 mole of K₃PO₄ produces 3 moles of potassium cation. The moles of potassium cation are:

0,0655 moles×3 = 0,1965 moles

The concentration is:

$\frac{0,1965 moles}{0,25L}$ = 0,786 M

The moles of K₃PO₄ are the same than moles of PO₄³⁻, thus, concentration of phosphate anion is the same than concentration of K₃PO₄. 0,262 M

I hope it helps!

4 0

3 years ago