How many neutrons are found in a stable isotope of uranium-235?

Explain why copper is used for the<br> roofs of some buildings and magnesium is not.

Scrat [10]

Answer:

Because of the less reactivity of copper.

Explanation:

As well as being resistant to the elements and thereby less likely to be affected by rainfall, hail, and mildew than other types of roofing, copper is also one of the most fireproof materials available. Copper is also highly resistant to thermal changes and thereby doesn't deteriorate quickly.

Magnesium would also corrode PDQ. Magnesium sheeting would also pose an unacceptably high fire hazard.

3 0

2 years ago

Choose three physical properties that can be used to identify pure substances. (select all that apply.) melting point degree of

ch4aika [34]

Malleable ductile and sonorous

5 0

3 years ago

The density of Mg is 1.74g/cm3. The density of strontium is 2.60g/cm3. What would you expect the density of Ca to be?

Tomtit [17]

The density of Ca will be between that of Mg and Sr

Explanation:

Ca, Mg and Sr are group II elements. They are called alkali earth metals. The correct order of the elements in this group are: Be, Mg, Ca, Sr, Ba and Ra.

Density is an intensive property of matter which describes the amount of matter(mass) per volume of a substance.

Density varies proportionally with mass. The higher the mass, the higher its density.
On the periodic table, atomic mass which the number of protons and neutrons in the nucleus of an atom increases down the group.
This implies a progradation in the value of density down the group. Therefore one expects that the value of density of Ca will fall between that of Mg and Sr. It cannot be more than 2.6g/cm³ nor less than 1.74g/cm³.

Learn more:

density brainly.com/question/2658982

mass number brainly.com/question/2597088

#learnwithBrainly

6 0

3 years ago

Consider the equilibrium reaction and its equilibrium constant expression. Br 2 ( g ) + 2 NO ( g ) − ⇀ ↽ − 2 NOBr ( g ) K = [ NO

zavuch27 [327]

Answer:

$K_2=\frac{[NOBr]^4_{eq}}{[NO]^4_{eq}[Br]^2_{eq}}$

Explanation:

Hello,

In this case, for the equilibrium condition, the equilibrium constant is defined via the law of mass action, which states that the division between the concentrations of the products over the concentration of the reactants at equilibrium equals the equilibrium constant, for the given reaction:

$2 Br_2 ( g ) + 4 NO ( g ) \rightleftharpoons 4NOBr ( g )$

The suitable equilibrium constant turns out:

$K_2=\frac{[NOBr]^4_{eq}}{[NO]^4_{eq}[Br]^2_{eq}}$

Or in terms of the initial equilibrium constant:

$K_2=K_1^2$

Since the second reaction is a doubled version of the first one.

Best regards.

5 0

3 years ago

What physical properties can be used to separate heterogeneous mixture's?

marysya [2.9K]

Evaporation, distillation, filtration and chromatography
Hope it help you, have a nice day

7 0

2 years ago