Advertisements
Advertisements
Cultivation practices and crop yield are related to environmental conditions. Explain.
Concept: undefined >> undefined
Differentiate between the following
Mixed cropping and Intercropping
Concept: undefined >> undefined
Advertisements
The mass per unit volume of a substance is called density.
(density = mass/volume).
Arrange the following in order of increasing density-
air, exhaust from chimneys, honey, water, chalk, cotton and iron.
Concept: undefined >> undefined
Tabulate the differences in the characteristics of states of matter.
Concept: undefined >> undefined
Comment upon the following:
rigidity, compressibility, fluidity, filling a gas container, shape, kinetic energy and density.
Concept: undefined >> undefined
Give reasons:
A gas fills completely the vessel in which it is kept.
Concept: undefined >> undefined
Give reasons:
A gas exerts pressure on the walls of the container.
Concept: undefined >> undefined
Give reasons:
We can easily move our hand in air, but to do the same through a solid block of wood, we need a karate expert.
Concept: undefined >> undefined
Give a reason for the following observation.
Naphthalene balls disappear with time without leaving any solid.
Concept: undefined >> undefined
Give a reason for the following observation.
We can get the smell of perfume sitting several metres away.
Concept: undefined >> undefined
Arrange the following substances in increasing order of forces of attraction between particles -
water, sugar, oxygen
Concept: undefined >> undefined
Write the steps you would use for making tea. Use the words: solution, solvent, solute, dissolve, soluble, insoluble, filtrate and residue.
Concept: undefined >> undefined
Pragya tested the solubility of three different substances at different temperatures and collected the data as given below (results are given in the following table, as grams of substance dissolved in 100 grams of water to form a saturated solution).
| Substance dissolved | Temperature in K | ||||
| 283 | 293 | 313 | 333 | 353 | |
| Solubility | |||||
| Potassium nitrate | 21 | 32 | 62 | 106 | 167 |
| Sodium chloride | 36 | 36 | 36 | 37 | 37 |
| Potassium chloride | 35 | 35 | 40 | 46 | 54 |
| Ammonium chloride | 24 | 37 | 41 | 55 | 66 |
- What mass of potassium nitrate would be needed to produce a saturated solution of potassium nitrate in 50 grams of water at 313 K?
- Pragya makes a saturated solution of potassium chloride in water at 353 K and leaves the solution to cool at room temperature. What would she observe as the solution cools? Explain.
- Find the solubility of each salt at 293 K. What salt has the highest solubility at this temperature?
- What is the effect of change of temperature on the solubility of a salt?
Concept: undefined >> undefined
Identify the solutions among the following mixtures.
- Soil
- Sea water
- Air
- Coal
- Soda water
Concept: undefined >> undefined
Fill in the gaps in the following table, illustrating differences between prokaryotic and eukaryotic cells.
| Prokaryotic cell | Eukaryotic cell | ||
| 1. | Size: generally small (1–10 µm) 1 µm = 10-6 m | 1. | Size: generally large (5-100 µm) |
| 2. | Nuclear region: ____________ ____________ and is known as _____. |
2. | Nuclear region: well defined and surrounded by a nuclear membrane. |
| 3. | Chromosome: single | 3. | More than one chromosome |
| 4. | Membrane-bound cell organelles absent |
4. |
____________ |
Concept: undefined >> undefined
How is a prokaryotic cell different from a eukaryotic cell?
Concept: undefined >> undefined
How does an Amoeba obtain its food?
Concept: undefined >> undefined
Which tissue makes up the husk of coconut?
Concept: undefined >> undefined
How many types of elements together make up the xylem tissue? Name them.
Concept: undefined >> undefined
How are simple tissues different from complex tissues in plants?
Concept: undefined >> undefined
