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3 years ago

What information guided Mendeleev as he placed elements in his periodic table

Chemistry

1 answer:

Rashid [163]3 years ago

6 0

Mendeleev created the first periodic table by ordering the elements by atomic mass, rather than their atomic numbers.

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How many grams are in 1.25 moles of Potassium hydroxide, KOH?<br><br>1 point

klasskru [66]

Answer:

There are 70 grams of KOH

Explanation:

First, we calculate the weight of 1 mol of KOH:

Weight 1 mol KOH: Weight K + Weight 0 + Weight H= 39g+ 1g+ 16g= 56 g/mol

1 mol-------56 g KOH

1,25 mol----x= (1,25 molx56 g KOH)/1 mol= <em>70 g KOH</em>

7 0

4 years ago

How many moles are contained in 2.0 L of N2 at standard temperature and pressure.

GuDViN [60]

0.091 moles are contained in 2.0 L of N2 at standard temperature and pressure.

Explanation:

Data given:

volume of the nitrogen gas = 2 litres

Standard temperature = 273 K

Standard pressure = 1 atm

number of moles =?

R (gas constant) = 0.08201 L atm/mole K

Assuming nitrogen to be an ideal gas at STP, we will use Ideal Gas law

PV = nRT

rearranging the equation to calculate number of moles:

PV = nRT

n = $\frac{PV}{RT}$

putting the values in the equation:

n = $\frac{1X2}{0.08201 X 273}$

n = 0.091 moles

0.091 moles of nitrogen gas is contained in a container at STP.

6 0

3 years ago

Fernando places 50 mL of HCl in a 100 mL beaker and 50 mL of NaOH in a 100 mL beaker. he places them on a scale together and mea

olchik [2.2K]

Answer:

The correct options are:

B. The HCl is the solute.

D. The H₂O is the solvent.

E. This mixture conducts electricity.

Explanation:

For the preparation of the HCl solution, 10 mL of HCl and 40 mL of water were mixed.

The compound that is present in the solution in a smaller ratio is the <u><em>solute</em></u> and the other compount -present in higher ratio- is the <u><em>solvent</em></u>.

So, the solute is HCl and the solvent is water (H₂O). Furthermore, water is considered as an universal solvent (for most of the polar and ionic compounds). According to this, the following options are correct:

B. The HCl is the solute.

D. The H₂O is the solvent.

Then, a condition for a solution that is able to conduct electricity is the presence of ions in the solution. When HCl is dissolved in water, it dissociates in ions according to the following equilibrium:

HCl ⇔ H⁺ + Cl⁻

The ions H⁺ and Cl⁻ are electrically charged so the solution can conduct electricity. According to this, the following option is also correct:

E. This mixture conducts electricity.

7 0

3 years ago

In November 1987, a massive iceberg broke loose from the antartic ice mass and floated free in the ocean. The chunk of ice was e

il63 [147K]

<h2>Answer:</h2>

1.58 × 10∧16 pools.

<h3>Explanation:</h3>

Given:

Length of ice berg= 98 miles = 1557716 meters

Width of iceberg = 25 miles = 40233.6 meters

Thickness of iceberg = 750 ft = 230 meters

Volume of water in a swimming pool = 24,000 gallons = 90850 liters

The volume of the ice berg:

Volume = Length . width . thickness

Volume = 1557716 . 40233.6 . 230 = 1,441, 468, 016, 5248 m3 = 1,441, 468, 016, 5248 × 10 ∧3 L.

1 pool contains liters of water: 90850 liters

1,441, 468, 016, 5248 × 10 ∧3 liters contains = 1/90850 . 1,441, 468, 016, 524.8 × 10 ∧3 .

= 1.100 . 1,441, 468, 016, 5248 × 10 ∧3 L.

= 1.58 × 10∧16 pools.

Hence 1.6 × 10∧16 pools will be filled with that chunk of ice.

4 0

3 years ago

To the nearest gram, what is the mass of of one spoonfull of sugar? g

Vaselesa [24]

Answer:

the mass of one spoonful of sugar to nearest gram is 10g

4 0

3 years ago