Explain the steps you would follow to make 500 mL of a 0.3 M solution of sucrose (C12H22011) in the lab.

see explanation

Explanation:

Solutions are prepared from one of three solute sources ...

- solid solute from manufacturer,

-liquid solute from manufacturer,

-stock concentrate of solute for dilution to lower concentrations.

In this problem, sucrose is a stock solid with a formula mass of 342.3 grams/mol. The amount of solid needed can be determined using the formula:

mass of solute needed (grams) = (Molarity needed x Volume needed in Liters x formula weight) / (decimal fraction purity of stock solid)

Molarity needed = 0.3M

Volume needed = 500 ml = 0.500 liters

Formula weight = 342.3 grams/mole

Purity factor (assumed) = 100% = 1.00 (should be posted on stock bottle label) For example, a 95% pure stock solid => purity factor of 0.95.

∴ grams of sucrose needed = (0.3M*)(0.500L)(342.3g/mole)/(1.00) =51.345 grams sucrose.

Measure 51.345 grams of sucrose into mixing vessel and add solvent water up to, but not to exceed 500 ml total volume. Mix until homogeneous.

a mercury barometer is a device that uses the physical properties of mercury in a tube to measure barometric pressure. mercury barometers are used for : -

1. measurement of atmospheric pressure  

2. determining the altitude of a place

3. weather forecasting

4. calibration and checking of aneroid barometers

5. application in fluid mechanics

6. measurement of pressure in aircrafts

7. surface weather analysis

8. preparation of barographs

9. usage in physical sciences like physics, astronomy & chemistry

10. preparation of aircraft altimeters

characteristics of mercury barometer : -

1.used to define and measure atmospheric pressure.

2.on the average at sea level the column of mercury rises to a height of about 760 mm.

3.this quantity is equal to 1 atmosphere.

4.it is also known as standard atmospheric pressure.

5.a barometer in which the weight of a column of mercury in a glass tube with a sealed top is balanced against that of the atmosphere pressing on an exposed cistern of mercury at the base of the mercury column, the height of the column varying with atmospheric pressure.

answer : a model is often used to explain and make things easier to understand when any scientific topic needs to be demonstrated and explained.

as in this case where a scientist wants to use a model to present the results of his detailed scientific investigation. he should do it as it will him to make the audience understand the concept in a much better way. also, it can be changed according to new scientific understandings.