Which part of the wave does the arrow point to?

All molecules have the same kinetic energy and hence the same speed. O True O False

topjm [15]

False...their speed differs

4 0

2 years ago

Relate the properties of atoms, their position in the periodic table, and their number of valence electrons to their chemical re

dalvyx [7]

Answer:

Explanation:

An atom is the smallest unit of an element that can take part in a chemical reaction. Atoms are made up of protons, neutrons and electrons. Atoms can exist as a monoatomic (such as in the case of Helium, Xenon and Neon) or as diatomic (such as in the case of oxygen and nitrogen). Atoms take part in a chemical reaction and there reactivity varies among themselves.

From the above, it can be deduced that atoms have protons, neutrons and electrons. The number of protons (which is positively charged) of an atom determines it's position on the periodic table because elements in the periodic table are arranged according to the number of protons (called atomic number). The electron(s) present in the outermost shell of each atom (called valence electrons) determines there chemical reactivity. What happens here is that, all atoms (except noble gases) want to achieve there duplet or octet configuration so as to become stable. This octet configuration means they want to have there outermost shell completely filled (with eight electrons or two electrons for duplet). They usually achieve this configuration by taking part in chemical reactions. Thus, when an atom has just one electron in it's outermost shell, it becomes easy to lose it to another atom by way of interacting with it in a chemical reaction. When it loses this single electron (valence electron) in it's outermost shell, it becomes stable with the inner completely filled shell (that would be the new outermost shell). Examples include Lithium, sodium and potassium. Sodium (with eleven electrons and three shells) would lose the single electron in it's outermost shell so as to have just two shells with the second shell completely filled with eight electrons. Thus, the more the valence electron to be lost to achieve the octet structure, the lesser the reactivity of the atom.

Also, an atom that has just one electron to complete it's own outermost shell and thus achieve it's octet structure is also highly reactive. This is also because it is easy for this atom to receive a single electron and become completely filled. Examples include chlorine, fluorine and iodine. Fluorine (with nine electrons and two shells) will easily accept one more electron so as to achieve it's octet structure with a completely filled outermost shell (of eight electrons). Thus, the lesser the electrons to be gained to achieve the octet configuration, the higher the chemical reactivity of such atoms. Noble gases have extremely low or no reactivity at all for this reason because it has a completely filled outermost shell (no losing or donating).

It should also be noted that metals (which are found on the left of the periodic table) exist as monoatomic while gases (which are found on the right), with the exception of noble gases, are mostly diatomic.

3 0

3 years ago

Suppose a 1.0 L solution contains 0.020 M in Cu(NO3)2, then 0.40 moles of NH3 are added. Assuming no change in volume, what is t

Rasek [7]

Answer:

$4.6*10^{-14}$ M

Explanation:

Concentration of $Cu^{2+} = [Cu(NO_3)_2]$ = 0.020 M

Constructing an ICE table;we have:

$Cu^{2+}+4NH_3_{aq} \rightleftharpoons [Cu(NH_3)_4]^{2+}_{(aq)}$

Initial (M) 0.020 0.40 0

Change (M) - x - 4 x x

Equilibrium (M) 0.020 -x 0.40 - 4 x x

Given that: $K_f =1.7*10^{13}$

$K_f } = \frac{[Cu(NH_3)_4]^{2+}}{[Cu^{2+}][NH_3]^4}$

$1.7*10^{13} = \frac{x}{(0.020-x)(0.40-4x)^4}$

Since x is so small; 0.40 -4x = 0.40

Then:

$1.7*10^{13} = \frac{x}{(0.020-x)(0.0256)}$

$1.7*10^{13} = \frac{x}{(5.12*10^{-4}-0.0256x)}$

$1.7*10^{13}(5.12*10^{-4} - 0.0256x) = x$

$8.704*10^9-4.352*10^{11}x =x$

$8.704*10^9 = 4.352*10^{11}x$

$x = \frac{8.704*10^9}{4.352*10^{11}}$

$x = 0.0199999999999540$

$Cu^{2+}= 0.020 - 0.019999999999954$

$Cu^{2+} = 4.6*10^{-14}$ M

8 0

3 years ago

A 44% wt/wt solution of H2SO4 has a density of 1.343g/ml. What mass of H2SO4 is 60ml of this solution?

horsena [70]

Answer: The mass of sulfuric acid present in 60 mL of solution is 34.1 grams

Explanation:

We are given:

44 % (m/m) solution of sulfuric acid. This means that 44 grams of sulfuric acid is present in 100 grams of solution.

To calculate volume of a substance, we use the equation:

$\text{Density of substance}=\frac{\text{Mass of substance}}{\text{Volume of substance}}$

Density of solution = 1.343 g/mL

Mass of solution = 100 g

Putting values in above equation, we get:

$1.343g/mL=\frac{100g}{\text{Volume of solution}}\\\\\text{Volume of solution}=\frac{100g}{1.343g/mL}=77.46mL$

To calculate the mass of sulfuric acid present in 60 mL of solution, we use unitary method:

In 77.46 mL of solution, mass of sulfuric acid present is 44 g

So, in 60 mL of solution, mass of sulfuric acid present will be = $\frac{44g}{77.46mL}\times 60mL=34.1g$

Hence, the mass of sulfuric acid present in 60 mL of solution is 34.1 grams

3 0

3 years ago

A drought hits the habitat of a semi-aquatic bird population. All ponds dry up, and fish populations decline. There are two grou

alexandr1967 [171]

Answer:

The population of the long-legged birds decreases.

Explanation:

The population of the short-legged birds increases whereas the population of long-legged birds decreases due to availability of food in that environment. The long-legged birds feed on fish whose population decreases due to drought conditions so the population of long-legged birds also decreases while on the other hand, the population of short-legged birds increases or remain the same because they feed on the insects and the insects are available in large amount and less affected by the drought conditions.

4 0

3 years ago