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
What is the concentration of sugar (C12H22O11) in mol L–1 if its 20 g are dissolved in enough water to make a final volume up to 2 L?
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.
Explain the term mole fraction.
Solve the following problem:
Find out the molar mass of the following compounds:
Sodium carbonate, decahydrate (Na2CO3.10H2O)
(At. mass: Cu = 63.5; S = 32; O = 16; H = 1; Na = 23; C = 12; Fe = 56; N = 14)
Solve the following problem:
Find out the molar mass of the following compounds:
Mohr’s salt [FeSO4(NH4)2SO4.6H2O]
(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:
3.75 × 10−1
Solve the following problem:
Write the following number in ordinary decimal form:
0.011 × 10−3
Solve the following problem:
Write the following number in ordinary decimal form:
14.3 × 10−2
Solve the following problem:
Perform the following calculation. Round off your answer to two digits.
`1/(3.40xx10^24)`
Solve the following problem:
Perform the following calculation. Round off your answer to two digits.
`33/(9.00xx10^-4)`
Perform each of the following calculations. Round off your answers to three digits.
(3.26104) (1.54106)
A 1.000 mL sample of acetone, a common solvent used as a paint remover, was placed in a small bottle whose mass was known to be 38.0015 g.
The following values were obtained when the acetone-filled bottle was weighed: 38.7798 g, 38.7795 g and 38.7801 g. How would you characterise the precision and accuracy of these measurements if the actual mass of the acetone was 0.7791 g?
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.
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) \[\ce{20 g of KOH in 200 mL of solution}\]
Which of the following terms are unitless?
(i) Molality
(ii) Molarity
(iii) Mole fraction
(iv) Mass percent
What is the difference between molality and molarity?
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?
What quantity (in mL) of a 45% acid solution of a monoprotic strong acid must be mixed with a 20% solution of the same acid to produce 800 mL of a 29.875% acid solution?
The molarity of urea (molar mass 60 g mol−1) solution by dissolving 15 g of urea in 500 cm3 of water is ______.
