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3 years ago

5

The symbol of an element is represented by (a) Calculate the number of neutrons in the atom of X. [1mark] (b) State the number o

f electrons in the atom of X.[1mark] (c) Write the electronic configuration of X.

1 answer:

aliina [53]3 years ago

3 0

Answer:

The question is incomplete.

A sample question and solution is given below.

Check the attachment for explanation.

Explanation:

Check the attachment below

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The four rows of data below show the boiling points for a solution with no solute, sucrose (C12H22O11), sodium chloride (NaCl),

choli [55]

Answer:

The four rows of data below show the boiling points for a solution with no solute, sucrose (C12H22O11), sodium chloride (NaCl), and calcium chloride (CaCl2) (not in that order). Which boiling point corresponds to calcium chloride?

A. 101.53° C

B. 100.00° C

C. 101.02° C

D. 100.51° C

Which of the following solutions will have the lowest freezing point?

A. 1.0 mol/kg sucrose (C12H22O11)

B. 1.0 mol/kg lithium chloride (LiCl)

C. 1.0 mol/kg sodium phosphide (Na3P)

D. 1.0 mol/kg magnesium fluoride (MgF2)

Which of the following compounds will be most effective in melting the ice on the roads when the air temperature is below zero?

A. sodium iodide (NaI)

B. magnesium sulfate (MgSO4)

C. potassium bromide (KBr)

D. All will be equally effective.

Four different solutions have the following vapor pressures at 100°C. Which solution will have the greatest boiling point?

A. 98.7 kPa

B. 96.3 kPa

C. 101.3 kPa

D. 100.2 kPa

Four different solutions have the following boiling points. Which boiling point corresponds to a solution with the lowest freezing point?

A. 101.2°C

B. 105.9°C

C. 102.7°C

D. 108.1°C

Explanation:

The following are the answers to the different questions:

The four rows of data below show the boiling points for a solution with no solute, sucrose (C12H22O11), sodium chloride (NaCl), and calcium chloride (CaCl2) (not in that order). Which boiling point corresponds to calcium chloride?

A. 101.53° C

Which of the following solutions will have the lowest freezing point?

D. 1.0 mol/kg magnesium fluoride (MgF2)

Which of the following compounds will be most effective in melting the ice on the roads when the air temperature is below zero?

A. sodium iodide (NaI)

Four different solutions have the following vapor pressures at 100°C. Which solution will have the greatest boiling point?

B. 96.3 kPa

Four different solutions have the following boiling points. Which boiling point corresponds to a solution with the lowest freezing point?

D. 108.1°C

5 0

3 years ago

Two students are given different samples of a substance and are instructed to determine the properties of the substance.Which st

musickatia [10]

Answer:

The boiling point of the substances

Explanation:

Because Boiling point is an intensive property.

5 0

3 years ago

Consider the following isotopic abundance data for argon (Ar) and silicon (Si):

pshichka [43]

Answer:

Explanation:

Molar mass of Argon

= 35.96755 x .00337 + 37.96272 x .00063 + 39.96240 x .99600

= .12121 + .0239165 + 39.80255

= 39.95

Molar mass of silicon

27.97693 x .9223 + 28.97649 x .0467 + 29.97376 x .0310

= 25.803 + 1.35320 + .929

= 28.08

b )

No of atoms of Si in 78.2 g = 78.2 x 6.02 x 10²³ / 28.08

= 16.76 x 10²³ .

c )

42 Ar / 40 Ar = 1.05006

42 Ar / 39.95 = 1.05006

42Ar = 41.95

2 )

C₁₆H₁₅F₂N₃O₄S

Mol weight = 16 x 12 + 1 x 15 + 2 x 19 + 3 x 14 + 4 x 16 + 32

= 192 + 15 + 38 + 42 + 64+ 32

= 383

No of molecules = .078 x 6.02 x 10²³ / 383

= 1.226 x 10²⁰ molecules .

7 0

2 years ago

What is the ph of a buffer prepared by adding 0.809 mol of the weak acid ha to 0.608 mol of naa in 2.00 l of solution? The disso

Anarel [89]

The pH of the buffer is 6.1236.

Explanation:

The strength of any acid solution can be obtained by determining their pH. Even the buffer solution strength of the weak acid can be determined using pH. As the dissociation constant is given, we can determine the pKa value as the negative log of dissociation constant value.

$pKa=-log[H] = - log [ 5.66 * 10^{-7}]\\ \\pka = 7 - log (5.66)=7-0.753=6.247\\\\pka = 6.247$

The pH of the buffer can be known as

$pH = pK_{a} + log[\frac{[A-]}{[HA]}}]$

The concentration of $[A^{-}] = Moles of [A]/Total volume = 0.608/2 = 0.304 M\\$

Similarly, the concentration of [HA] = $\frac{Moles of HA}{Total volume} = \frac{0.809}{2} = 0.404$

Then the pH of the buffer will be

pH = 6.247 + log [ 0.304/0.404]

$pH = 6.247 + log 0.304 - log 0.404=6.247-0.517+0.3936=6.1236$

So, the pH of the buffer is 6.1236.

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3 years ago

What effects do winds patterns have on climate

Nezavi [6.7K]

Prevailing winds bring air from one type of climate to another. For example, warm winds that travel over water tend to collect moisture as they travel; the water vapor in the air will condense as it moves into colder climates, which is why temperate coastal areas often receive heavy rainfall.

Hope it Helps! T^T

5 0

3 years ago