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3 years ago

Which elements have the greatest tendency to behave as oxidizing agents?

1 answer:

8 0

The force acting between two charged particles A and B is 5.2 x 105 newtons. Charges A and B are 2.4 x 102 meters apart. If the charge on particle A is 7.2 x 108 coulombs, what is the charge of particle B? (k 7 9.0 x 109 newton meters?/coulomb)

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In a nuclear fusion reaction, the mass of the products is(1) less than the mass of the reactants because some

dusya [7]

The correct answer is option 1. The mass of the products is less than the mass of the reactants because some of the mass has been converted to energy. Fusion reaction happens when two or more nuclei combine or collide to form an element with a higher atomic number. In this process, some of the matter of the fusing nuclei is converted to energy.

4 0

3 years ago

Phenolphthalein has a pKa of 9.7 and is colorless in its acid form and pink in its basic form. calculate [In-}/{HIn} for the fol

zvonat [6]

Answer:

1.58x10⁻⁵

2.51x10⁻⁸

0.0126

63.10

Explanation:

Phenolphthalein acts like a weak acid, so in aqueous solution, it has an acid form HIn, and the conjugate base In-, and the pH of it can be calculated by the Handerson-Halsebach equation:

pH = pKa + log[In-]/[HIn]

pKa = -logKa, and Ka is the equilibrium constant of the dissociation of the acid. [X] is the concentrantion of X. Thus,

i) pH = 4.9

4.9 = 9.7 + log[In-]/[HIn]

log[In-]/[HIn] = - 4.8

[In-]/[HIn] = $10^{-4.8}$

[In-]/[HIn] = 1.58x10⁻⁵

ii) pH = 2.1

2.1 = 9.7 + log[In-]/[HIn]

log[In-]/[HIn] = -7.6

[In-]/[HIn] = $10^{-7.6}$

[In-]/[HIn] = 2.51x10⁻⁸

iii) pH = 7.8

7.8 = 9.7 + log[In-]/[HIn]

log[In-]/[HIn] = -1.9

[In-]/[HIn] = $10^{-1.9}$

[In-]/[HIn] = 0.0126

iv) pH = 11.5

11.5 = 9.7 + log[In-]/[HIn]

log[In-]/[HIn] = 1.8

[In-]/[HIn] = $10^{1.8}$

[In-]/[HIn] = 63.10

6 0

3 years ago

How is the mass of 1 mole of an element determined? O A. It is equal to the atomic mass times Avogadro's number. O B. It is the

evablogger [386]

Answer:

Avogadro's number is the number of particles in one mole of anything. In this context, it is the number of atoms in one mole of an element. It's easy to find the mass of a single atom using Avogadro's number. Simply divide the relative atomic mass of the element by Avogadro's number to get the answer in grams.

4 0

3 years ago

If the average rate of sediment accumulation is 3 cm/1000years, how long would be required for sediments to completely bury seam

stira [4]

Answer:

500,050000 years

Explanation:

Given that :

Rate of Accumulation = 3cm/ 1000 years

Height of seamounts = 1.5km

Representing height of seamounts in cm;

(1.5 *1000 * 100) = 1500150 cm

Time taken = height / rate

Time taken = (1500150 cm / 3cm) * 1000

Time taken = 500,050000 years

5 0

3 years ago

Write the formula for potassium oxide. why do you not need prefixes in the name

Molodets [167]

Potassium oxide: K₂O.

There's no need for prefixes since K₂O is an ionic compound.

<h3>Explanation</h3>

Find the two elements on a periodic table:

Potassium- K- on the left end of period four.
Oxygen- O- near the right end of periodic two.

Elements on the bottom-left corner of the periodic table are metals. Those on the top-right corner are nonmetals.

Potassium is a metal,
Oxygen is a nonmetal.

A metal and a nonmetal combine to form an ionic compound. Potassium oxide is likely to be an ionic compound. It contains two types of ions:

Potassium ions: Potassium is group 1 of the periodic table. It is an alkaline metal. Like other alkaline metals such as sodium Na, potassium K tends to lose one electron and form ions of charge +1 in compounds. The ion would be K⁺.

Oxide ions from oxygen: Oxygen is the second most electronegative element on the periodic table. It tends to gain two electrons and form the oxide ion $\text{O}^{2-}$ when it combines with metals.

The two types of ions carry opposite charges. They shall pair up at a certain ratio such that they balance the charge on each other. The charge on each $\text{O}^{2-}$ ion is twice that on a $\text{K}^{+}$ ion. Each $\text{K}^{+}$ would pair up with two $\text{O}^{2-}$ . Hence the subscript in the formula: $\text{K}_{\bf 2}\text{O}$ .

There are two classes of compounds:

Covalent compounds, which need prefixes, and
Ionic compounds, which need no prefix.

Prefixes are needed only in covalent compounds. For instance in the covalent compound carbon dioxide $\text{CO}_2$ , the prefix di- indicates that there are two oxygen atoms in the formula $\text{CO}_2$ . However, there's no need for prefix in ionic compounds such as $\text{K}_2\text{O}$ .

7 0

3 years ago