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2 years ago

Describes how Anders Celsius devised the temperature scale that bears his name

1 answer:

3 0

He used a tube of mercury and marked the height of the mercury when placed in an ice bath as 0 degrees celsius, when he placed the tube in a boiling, he marked the height of mercury and called that 100 degrees celsius, he marked it linearly between 0-100 degrees celsius

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3. Discuss the difference between molarity and molality, state the units of each, state the symbol for each, and give an example

dangina [55]

Molality(m) or molal concentration is a measure of concentration and it refers to amount of substance in a specified amount of mass of the solvent. Used unit for molality is mol/kg which is also sometimes denoted as 1 molal. It is equal to the moles of solute (the substance being dissolved) divided by the kilograms of solvent (the substance used to dissolve).

Molarity(M) or molar concentration is also a measure of concentration and represents the amount of substance per unit volume of solution(number of moles per litre of solution. Used unit for molarity is mol/L or M. A solution with a concentration of 1 mol/L is equivalent to 1 molar (1 M).

Molality is preferred when the temperature of the solution varies, because it does not depend on temperature, (neither number of moles of solute nor mass of solvent will be affected by changes of temperature), while molarity changes as temperature changes(volume of solution changes as temperature changes).

4 0

2 years ago

Which of the following are in the human brain?

mezya [45]

The correct answer is D :)

5 0

2 years ago

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Which two properties are characteristic of ionic compounds?

natima [27]

They are colourless solids (salts) that do not conduct electricity when solid, but conduct electricity in aqueous solution as the ions (that carry charge) are free to move.

They have a high melting point due to the strong electrostatic forces of attraction between oppositely charged ions

Best regards

3 0

2 years ago

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10. What is the Kinetic Energy of a 100 kg object that is moving with a speed of 13.5 m/s?

marissa [1.9K]

Answer:

$100 \times 13.5 = ikw n bahaa$

IKAW na mag tayms

7 0

2 years ago

2. Answer the following questions about a sample of calcium phosphate:

weqwewe [10]

Answer:

a) 310.18 g/mol

b) 4.352 moles Ca3(PO4)2

c) 2.6 * 10^24 molecules

d) 5.24 * 10^24 P atoms

e)13.056 moles Ca

f)10825.3 grams

Explanation:

Step 1: Data given

Atomic mass of Ca = 40.08 g/mol

Atomic mass of P = 30.97 g/mol

Atomic mass of O = 16.0 g/mol

Step 2: Calculate molecular weight of Ca3(PO4)2

Molecular weight of Ca3(PO4)2 = 3*atomic mass of Ca + 2* atomic mass of P and 8* atomic mass of O

Molecular weight of Ca3(PO4)2 = 3*40.08 + 2*30.97 + 8*16.0 = 310.18 g/mol

Step 3: Calculate moles of Ca3(PO4)2 in 1350 grams

Moles Ca3(PO4)2 = mass Ca3(PO4)2 /molar mass

Moles Ca3(PO4)2 = 1350 grams / 310.18 g/mol

Moles Ca3(PO4)2 = 4.352 moles

Step 4: Calculate molecules in 1350 grams

Molecules = moles * number of Avogadro

Molecules = 4.352 moles * 6.02 * 10^23

Molecules = 2.6 *10^24 molecules

Step 5: Calculate moles Phosphorus

For 1 mol Ca3(PO4)2 we need 2 moles P

For 4.352 moles Ca3(PO4)2 we have 2*4.352 = 8.704 moles

Step 6: Calculate P atoms

Atoms P = 8.704 moles * 6.02*10^23

Atoms P = 5.24 * 10^24 P atoms

Step 7: Calculate moles Calcium in 1350 grams

For 1 mol Ca3(PO4)2 we have 3 moles Ca

For 4.352 moles we have 3*4.352 = 13.056 moles Ca

Step 8: Calculate mass of 2.1 * 10^25 molecules of Ca3(PO4)2

Moles Ca3(PO4)2 = 2.1 * 10^25 / 6.02 * 10^23

Moles Ca3(PO4)2 = 34.9 moles

Mass Ca3(PO4)2 = 34.9 moles * 310.18 g/mol

Mass Ca3(PO4)2 = 10825.3 grams

4 0

2 years ago