Advertisements
Advertisements
प्रश्न
Solve the following problem:
Your laboratory partner was given the task of measuring the length of a box (approx 5 in) as accurately as possible, using a metre stick graduated in milimeters. He supplied you with the following measurements:
12.65 cm, 12.6 cm, 12.65 cm, 12.655 cm, 126.55 mm, 12 cm.
State which of the measurements you would accept, giving the reason.
Advertisements
उत्तर
The metre stick is graduated in millimetres i.e. 1 mm to 1000 mm, and 1 mm = 0.1 cm. Therefore, if length is measured in centimetres, the least count of metre stick is 0.1 cm. The results 12.6 cm has the least count of 0.1 cm and is acceptable result.
APPEARS IN
संबंधित प्रश्न
To make a saturated solution, 36 g of sodium chloride is dissolved in 100 g of water at 293 K. Find its concentration at this temperature.
If the density of methanol is 0.793 kg L–1, what is its volume needed for making 2.5 L of its 0.25 M solution?
A sample of drinking water was found to be severely contaminated with chloroform, CHCl3, supposed to be carcinogenic in nature. The level of contamination was 15 ppm (by mass).
- Express this in percent by mass.
- Determine the molality of chloroform in the water sample.
Dinitrogen and dihydrogen react with each other to produce ammonia according to the following chemical equation:
\[\ce{N2 (g) + 3H2 (g) → 2NH3 (g)}\]
(i) Calculate the mass of ammonia produced if 2.00 × 103 g dinitrogen reacts with 1.00 × 103 g of dihydrogen.
(ii) Will any of the two reactants remain unreacted?
(iii) If yes, which one and what would be its mass?
Calculate the molarity of a solution of ethanol in water in which the mole fraction of ethanol is 0.040 (assume the density of water to be one).
Why does the molarity of a solution depend upon temperature?
Solve the following problem:
Find out the molar mass of the following compounds:
Copper sulphate crystal (CuSO4.5H2O)
(At. mass: Cu = 63.5; S = 32; O = 16; H = 1; Na = 23; C = 12; Fe = 56; N = 14)
Solve the following problem:
Write the following number in ordinary decimal form:
3.49 × 10−11
Solve the following problem:
Write the following number in ordinary decimal form:
5.16 × 104
Solve the following problem:
Perform the following calculation. Round off your answer to two digits.
`1/(3.40xx10^24)`
Perform the following calculation. Round off your answer to three digits.
(8.39 107) (4.53 109)
Name the process associated with the following
A drop of ink placed on the surface of water contained in a glass spreads throughout the water.
What are the favourable qualities given to gold when it is alloyed with copper or silver for the purpose of making ornaments?
Give an example of each mixture having the following characteristics. Suggest a suitable method to separate the components of this mixture
Two immiscible liquids.
Non-metals are usually poor conductors of heat and electricity. They are non-lustrous, non-sonorous, non-malleable and are coloured.
Name a lustrous non-metal.
If the concentration of glucose \[\ce{(C6H12O6)}\] in blood is 0.9 g L–1, what will be the molarity of glucose in blood?
What will be the molality of the solution containing 18.25 g of \[\ce{HCl}\] gas in 500 g of water?
Sulphuric acid reacts with sodium hydroxide as follows:
\[\ce{H2SO4 + 2NaOH -> Na2SO4 + 2H2O}\]
When 1 L of 0.1 M sulphuric acid solution is allowed to react with 1 L of 0.1 M sodium hydroxide solution, the amount of sodium sulphate formed and its molarity in the solution obtained is:
(i) 0.1 mol L–1
(ii) 7.10 g
(iii) 0.025 mol L–1
(iv) 3.55 g
Which of the following solutions have the same concentration?
(i) \[\ce{20 g of NaOH in 200 mL of solution}\]
(ii) \[\ce{0.5 mol of KCl in 200 mL of solution}\]
(iii) \[\ce{40 g of NaOH in 100 mL of solution}\]
(iv) \[\ce{20 g of KOH in 200 mL of solution}\]
Match the following physical quantities with units
| Physical quantity | Unit |
| (i) Molarity | (a) g mL–1 |
| (ii) Mole fraction | (b) mol |
| (iii) Mole | (c) Pascal |
| (iv) Molality | (d) Unitless |
| (v) Pressure | (e) mol L–1 |
| (vi) Luminous intensity | (f) Candela |
| (vii) Density | (g) mol kg–1 |
| (viii) Mass | (h) Nm–1 |
| (i) kg |
The molarity of pure water is ______.
An aqueous KCl solution of density 1.20 g mL-1 has a molality of 3.30 mol kg-1. The molarity of the solution in mol L-1 is ______. (Nearest integer)
With increase of temperature, which of these changes?
250 g solution of D-glucose in water contains 10.8% of carbon by weight. The molality of the solution is nearest to ______.
(Given: Atomic weights are H, 1u; C, 12u; O, 16u)
Molarity of liquid HCl will be if the density of the solution is 1.17 g/cc.
Find the molality of solution if boiling point increases by 1.75 K and molal elevation constant of solvent is 5K kg mol-1.
