What is the gram formula mass of potassium hydroxide (KOH)?

Which of the followings are true about D-glucose and L-glucose? A. They are furanose B. They are stereoisomers C. They are enant

zaharov [31]

Answer:

B. They are stereoisomers

C. They are enantiomers

Explanation:

Let us consider all the options

A. D and L-glucose are not necessarily furanose, they can also be in free form (open chain) or as a six-membered ring (pyranose)

B. These sugars are stereoisomers as they have the same molecular formula, same bonds but with the different spacial arrangement.

C. Two structures are called enantiomers, if they are stereoisomers and are mirror images of each other and are not-superimposable. The given pair of structures satisfy these conditions

D. Epimers are diastereoisomers (same molecular formula and connectivity having a different spacial arrangement but are not mirror images and non-superimposable) with only one different stereocenter (if there are more than one). This is not the case

E. All monosaccharides (any sugar that cannot be hydrolysed to a simpler sugar) are reducing sugars. So, this option is invalid

4 0

3 years ago

Which of the following UV rays has the highest energy that damages your skin the most?

Sergio [31]

The answer is b) UVB

7 0

2 years ago

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

inysia [295]

Answer: The molar mass of the unknown compound is 223.2 g/mol

Explanation:

To calculate the concentration of solute, we use the equation for osmotic pressure, which is:

$\pi=iMRT$

where,

$\pi$ = osmotic pressure of the solution = 8.44 torr

i = Van't hoff factor = 1 (for non-electrolytes)

M = molarity of solute = ?

R = Gas constant = $62.3637\text{ L torr }mol^{-1}K^{-1}$

T = temperature of the solution = $25^oC=[273+25]=298K$

Putting values in above equation, we get:

$8.44torr=1\times M\times 62.3637\text{ L. torr }mol^{-1}K^{-1}\times 298K\\\\M=\frac{8.44}{1\times 62.3637\times 298}=4.54\times 10^{-4}M$

To calculate the molecular mass of solute, we use the equation used to calculate the molarity of solution:

$\text{Molarity of the solution}=\frac{\text{Mass of solute}\times 1000}{\text{Molar mass of solute}\times \text{Volume of solution (in mL)}}$

We are given:

Molarity of solution = $4.54\times 10^{-4}M$

Given mass of unknown compound = 15.2 mg = 0.0152 g (Conversion factor: 1 g = 1000 mg)

Volume of solution = 150.0 mL

Putting values in above equation, we get:

$4.54\times 10^{-4}M=\frac{0.0152\times 1000}{\text{Molar mass of unknown compound}\times 150.0}\\\\\text{Molar mass of unknown compound}=\frac{0.0152\times 1000}{150.0\times 4.54\times 10^{-4}}=223.2g/mol$

Hence, the molar mass of the unknown compound is 223.2 g/mol

5 0

3 years ago

Which structures main function is to produce food (sugar) in a plant

bija089 [108]

Chloroplasts is the answer

3 0

3 years ago

Using the phase diagram for water, what phase is water at 0.01 degrees Celsius and 0.0060 atmospheres?

anzhelika [568]

Answer: at 0.01 °C and 0.0060 atm the three phases (solid, liquid and gas)


Explanation:


1) Water at 0.0060 atm and 0.01° C is at its triple point.


2) The triple point is the point in the phase diagram at which the three physical states coexist: gas, liquid and solid.

3) That means that water can freeze and boil at the same time. In fact they can happen any of the six changes of phase: freezing (liquid to solid), melting (solid to liquid), evaporation (liquid to gas), condensation (gas to liquid), sublimation (solid to gas), and deposition (gas to solid).

The phase diagram is unique for any substance, meaning that it is different for different substances: the normal boiling and melting points are different.

8 0

4 years ago