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3 years ago

Gr6_Sci_Assesment\FY18

Chemistry

1 answer:

Rzqust [24]3 years ago

5 0

Answer:

A. The student did not include the effect of friction in his calculation.

Explanation:

They are not equal because kinetic energy is relative to the state of other objects in its environment such as friction which doesn't apply to potential energy.

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A 150.0mL sample of an aqueous solution at 25C contains 15.2mg of an unknown nonelectrolyte compound. If the solution has an osm

Nookie1986 [14]

Answer:

MM = 225.11 g/mol

Explanation:

In this case, let's analyze the data.

We have a 15.2 mg of an unknown electrolyte in 150 mL of solution. The osmotic pressure is 8.44 Torr, and we want the molecular mass of the unknown.

The osmotic pressure can be calculated using the following expression:

π = CRT (1)

π: osmotic pressure (8.44 Torr * 1 atm / 760 Torr = 0.011 atm)

C: Concentration of the unknown in the solution

R: universal constant of gases (0.082 L atm / K mol)

T: temperature in Kelvin (25 + 273 = 298 K)

From this expression, we can either solve for C, and then use another expression to calculate the molecular mass, or we can just replace the expressions in the above formula, to get the direct molecular mass. In this case, we'll follow the second method.

Concentration or molarity of a substance can be calculated using:

C = moles / V (2)

And moles can be calculated using this expression:

moles = m / MM (3)

Replacing (3) in (2), and then in (1) we have:

C = m / MM * V

π = m * RT / MM * V (4)

and now, we can solve for MM:

MM = mRT / π V (5)

Now, we just need to replace the given data into the above expression to get the value of the molecular mass:

MM = (15.2 / 1000) * 0.082 * 298 / 0.011 * 0.150

Hope this helps

3 0

3 years ago

Describe and compare the building blocks, general structires and biological functions of carbohydrates lipids proteins and nucle

Nata [24]

Answer:

Explanation:

Carbohydrates are basically composed of Carbon, Hydrogen and Oxygen having the general formula CnH2nOn.

There are 3 types of carbohydrates which are dependent on the number of "n"

Monosaccharides which are n>3 (Triose) are the aldose and ketose.

They are the simpleat and smallest form and they are Glucose, fructose and galactose

Disaccharides are structure of the combination of the monosaccharides by glycosidic bond and they are sucrose, lactose, maltose etc

Polysaccharides are the largest and insoluble form of carbohydrates. They are cellulose, starch, glycogen etc.

Lipids(triglycerides) are solid fats or series of repeated fats at room temperature, they are insoluble in water both soluble in some organic solvents. They are also composed of glycerides (3 molecules). Its structure is composed of two parts, the soluble part composing of the -COOH group and the insoluble part that can be saturated or unsaturated hydrocarbon chain

Saturated fats - CH3(CH2)nCOOH

Their types are phospholipids, glycolipids etc

Proteins are polymers of peptides called polypeptides. The bond linking the structure together is called a peptide bond (-CONH-). They form chains of amino acid.

There are 4 levels of protein structures and they are

The primary structure defines the basic straight chain structure of an amino acid. They form the basis of genetic mutation.

Secondary structure involves the folding of this chain into alpha helix or beta pleated.

Tertiary structure is a 3-D structure that involves the hydrophobic and Hydrophilic parts pf the structure. The hydrophobic part apreads outwards while the hydrophyllic parts curve inwards by the action of van der waals forces.

Tertiary structure in this case is the example of the Haemoglobin

Nucleic acids is the building block for RNA and DNA (ribo- and Deoxyribonucleic acid). This is composed of a nitrogenous base which can either be purine or pyrimidine bases, a ribose sugar (5- Carbon sugar and phosphate group

The bond holding the nucleotides together is called phosphodiester bond.

6 0

3 years ago

Cuál será el volumen de ácido clorhídrico concentrado, de densidad 1,19g/mL del 38% de ácido en peso, que se necesita para prepa

julsineya [31]

Answer:

Sorry I speak English can't help

7 0

3 years ago

DIMENSIONAL ANALYSIS PLSSSS convert 19 inches to feet(show work)

Anna [14]

19 in = 1.6 ft

You know that

12 in = 1 ft

If you divide both sides by 12 in, you get the conversion factor: 1 = 1 ft/12 in.

If you divide both sides by 1 ft, you get the conversion factor: 12 in/1 ft = 1.

Both are conversion factors because they both equal one and multiplying a measurement by one does not change its value.

You choose the conversion that gives you the correct dimensions for your answer. It must have the correct dimensions on top (in the numerator),

Thus, to convert 19 in to ft, you use the conversion factor with “ft” on the top.

∴ Length = 19 in × (1 ft/12 in) = 1.6 ft

6 0

2 years ago

The shielding of electrons gives rise to an effective nuclear charge, Zeff, which explains why boron is larger than oxygen. Esti

nadezda [96]

The solution would be like this for this specific problem:

(atomic number) - (core electrons)

Boron:

Atomic number: 5
Core electrons: 2

Boron will have the following: 2 core electrons and 3 valence electrons.
(atomic number) - (core electrons)------> (5) - (2) = +3

Oxygen: 
Atomic number: 8 
Core electrons: 2

Boron will have the following: 2 core electrons and 6 valence electrons. 
(atomic number) - (core electrons)------> (8) - (2) = +6 |

So the answer would be +3 and +6.

I hope this helps and if you have any further questions, please don’t hesitate to ask again.

3 0

3 years ago