Which element is located in period 4?

What is the molality of an aqueous KCl solution with a mole fraction of KCl, XKCl = 0.175? (The molar mass of KCl = 74.55 g/mol

NARA [144]

Answer:

The molality of the KCl solution is 11.8 molal

Explanation:

Step 1: Data given

Mol fracrion KCl = 0.175

Molar mass KCl = 74.55 g/mol

Molar mass H2O = 18.02 g/mol

Step 2: Calculate mol fraction H2O

mol fraction H2O = 1 - 0.175 = 0.825

Step 3: Calulate mass of H2O

Suppose the total moles = 1.0 mol

Mass H2O = moles H2O * molar mass

Mass H2O = 0.825 * 18.02 g/mol

Mass H2O = 14.87 grams = 0.01487 kg

Step 4: Calculate molality

Molality KCl = 0.175 / 0.01487 kg

Molality KCl = 11.8 molal

The molality of the KCl solution is 11.8 molal

5 0

3 years ago

Consider 80.0-g samples of two different compounds consisting of only carbon and oxygen. One of the compounds consists of 21.8 g

goldenfox [79]

Answer:

<u><em>Ratio of the mass carbon that combines with 1.00 g of oxygen in compound 2 to the mass of carbon that combines with 1.00 g of oxygen in compound 1 = 2</em></u>

Explanation:

First, detemine the mass of oxygen in the two samples by difference:

mass of oxygen = mass of sample - mass of carbon

Item Compound 1 Compound 2

Sample 80.0 g 80.0 g

Carbon 21.8 g 34.3 g

Oxygen: 80.0 g - 21.8g = 58.2 g 80.0 g - 34.3 g = 45.7 g

Second, determine the ratios of the masses of carbon that combine with 1.00 g of oxygen:

For each sample, divide the mass of carbon by the mass of oxygen determined above:

Sample Mass of carbon that combines with 1.00 g of oxygen

Compound 1 21.8 g / 58.2 g = 0.375

Compound 2 34.3 g / 45.7 g = 0.751

Third, determine the ratio of the masses of carbon between the two compounds.

Divide the greater number by the smaller number:

Ratio = 0.751 / 0.375 = 2.00 which in whole numbers is 2

6 0

3 years ago

How does the temperature of the air cause a breeze to blow toward the land?

Anit [1.1K]

Answer:

The warm air over the land will rise throughout the day, causing low pressure at the surface. Over the water, high surface pressure will form because of the colder air. ... The wind will blow from the higher pressure over the water to lower pressure over the land causing the sea breeze.

Explanation:

<h2><u>PLZ MARK AS BRAINLEST!!!</u></h2>

8 0

2 years ago

A hypothetical element has an atomic weight of 48.68 amu. It consists of three isotopes having masses of 47.00 amu, 48.00 amu, a

Morgarella [4.7K]

Answer : The percent abundance of the heaviest isotope is, 78 %

Explanation :

Average atomic mass of an element is defined as the sum of masses of each isotope each multiplied by their natural fractional abundance.

Formula used to calculate average atomic mass follows:

$\text{Average atomic mass }=\sum_{i=1}^n\text{(Atomic mass of an isotopes)}_i\times \text{(Fractional abundance})_i$