Description : What are metalloids? Explain by giving examples. -Chemistry-10
Last Answer : Metalloids are elements which show some properties of metals and some properties of non-metals. Examples: Silicon, boron, arsenic, antimony, germanium, tellurium, polonium.
Description : What happens when baking soda is heated? -Chemistry-10
Last Answer : Sodium hydrogen carbonate (also known as sodium bicarbonate or bicarbonate of soda) has the chemical formula NaHCO3. When it is heated above about 80°C it begins to break down, forming sodium carbonate, water and carbon dioxide. This type of reaction is called a thermal decomposition.
Description : (i) Substances oxidised is Na as it gains oxygen and oxygen is reduced. (ii) Substances reduced is Cu as hydrogen is oxidised as it gains oxygen. -Chemistry-10
Last Answer : During this reaction, the sodium is gaining oxygen and is being oxidized. Oxygen is getting reduced. During this reaction, copper oxide is losing oxygen and is being reduced. The hydrogen is gaining oxygen and is being oxidized.
Description : Identify the substances that are oxidised and the substances which are reduced in the following reactions. (i) 4Na(s) + O2(g) → 2Na2O(s) (ii) CuO (s) + H2(g) → Cu (s) + H2O(l) -Chemistry-10
Last Answer : (i) Substances oxidised is Na as it gains oxygen and oxygen is reduced. (ii) Substances reduced is Cu as hydrogen is oxidised as it gains oxygen.
Description : Give an example of a double displacement reaction other than the one given in Activity 1.10 -Chemistry-10
Last Answer : Sodium hydroxide and hydrochloric acid react to form sodium chloride and water.
Description : An iron nail is dipped in the solution of copper sulphate for about 30 minutes. State the change in colour observed. Give reason for the change. -Chemistry-10
Last Answer : When an iron nail is dipped in copper sulphate solution, the displacement reaction takes place. The colour of copper sulphate solution fades due to the formation of light green solution of iron sulphate.
Description : Why does the colour of copper sulphate solution change when an iron nail is dipped in it ? -Chemistry-10
Description : Why is the amount of gas collected in one of the test tubes in text book Activity 1.7 (i.e., electrolysis of water) double of the amount collected in the other? Name this gas. -Chemistry-10
Last Answer : In Activity 1.7, water is electrolysed to give H2 gas at one electrode and O2 gas at the other electrode. 2H2O(l) → 2H2(g) + O2(g) Thus two molecules of water on electrolysis give two ... oxygen gas or in other words the amount of hydrogen gas collected would be double than that of oxygen gas.
Description : A solution of a substance ‘X’ is used for white washing. (i) Name the substance ‘X’ and write its formula. (ii) Write the reaction of the substance ‘X’ named in (i) above with water. -Chemistry-10
Last Answer : (i) The substance whose solution in water is used for white washing is calcium oxide (or quick lime). Its formula is CaO.
Description : Write a balanced chemical equation with state symbols for the following reactions : -Chemistry-10
Last Answer : (i) BaCl2 (aq) + Na2SO4 (aq) → BaSO4(s) + 2NaCl (aq) (ii) NaOH (aq) + HCl(aq) → NaCl(aq) + H2O(l)
Description : Write the balanced equation for the following chemical reactions. (i) Hydrogen + Chlorine → Hydrogen chloride (ii) Barium chloride + Aluminium sulphate → Barium sulphate + Aluminium chloride (iii) Sodium + Water → Sodium hydroxide + Hydrogen -Chemistry-10
Last Answer : (i) H2 + Cl2 → 2HCl (ii) 3 BaCl2 + Al2(SO4)3 → BaSO4 + 2 AlCl3 (iii) 2Na + 2H2O → 2NaOH + H2↑
Description : Why should a magnesium ribbon be cleaned before burning in air ? -Chemistry-10
Last Answer : Magnesium gets covered with a layer of magnesium oxide when kept in air for a long time. This layer hinders the burning of magnesium. Hence, it is to be cleaned before burning.
Description : 15. An object 2 cm high is placed at a distance of 64 cm from a white screen. On placing a convex lens at a distance of 32 cm from the object it is found that a distinct image of the object is formed on the screen. What is the focal length of the conve -Chemistry-10
Last Answer : Since, object-screen distance is double of object-lens separation, the object is at a distance of 2f from the lens and the image should be of the same size of the object.
Description : 14. An object 2 cm in size is placed 30 cm in front of a concave mirror of focal length 15 cm. At what distance from the mirror should a screen be placed in order to obtain a sharp image? What will be the nature and the size of the -Chemistry-10
Last Answer : Answer. hope this helps you
Description : 13. A ray of light, incident obliquely on a face of a rectangular glass slab placed in air, emerges from the opposite face parallel to the incident ray. State two factors on which the lateral displacement of the emergent ray depends. [Foreign] -Chemistry-10
Last Answer : Lateral displacement depends on the: angle of incidence, thickness of slab, and refractive index of the material. (any two)
Description : 12. Draw ray diagrams to represent the nature, position and relative size of the image formed by a convex lens for the object placed: -Chemistry-10
Description : 10. Which kind of mirrors are used in the headlights of a motor-car and why? [Foreign] -Chemistry-10
Last Answer : Answer. Concave mirror, to get the parallel beam of light.
Description : 11. Explain with the help of a diagram, why a pencil partly immersed in water appears to be bent at the water surface. [Delhi] -Chemistry-10
Last Answer : Answer. Light from different points on the pencil, immersed in water refracts and appears to come from a point above the original position.
Description : 7. Redraw the given diagram and show the path of the refracted ray: [All India(C)] -Chemistry-10
Description : 6. “The refractive index of diamond is 2.42”. What is the meaning of this statement in relation to speed of light? [Delhi] -Chemistry-10
Description : 5. The refractive indices of four media A, B, C and D are given in the following table: -Chemistry-10
Last Answer : (i) Minimum change is seen as light moves between 1.50 and 1.52, i.e. B and C. (ii) Maximum change when light moves between 1.33 and 2.40, i.e. A and D.
Description : 4. If a light ray IM is incident on the surface AB as shown, identify the correct emergent ray. [Delhi (C)] -Chemistry-10
Last Answer : Answer. Ray NQ, as it has to be parallel to ray OS.
Description : 3. Draw the ray diagram in each case to show the position and nature of the image formed when the object is placed: -Chemistry-10
Last Answer : Answer. Nature of image: Real, inverted and same size image is formed at the centre of curvature. Nature of image: Virtual, enlarged and erect image is formed behind the mirror. Nature of image: ... image: Virtual, erect and diminished image is formed between O and F on the same side of object.
Description : 2. An object 50 cm tall is placed on the principal axis of a convex lens. Its 20 cm tall image is formed on the screen placed at a distance of 10 cm from the lens. Calculate the focal length of the lens. [All India] -Chemistry-10
Last Answer : this is the answer for the respected question
Description : 1. A concave lens has focal length of 20 cm. At what distance from the lens a 5 cm tall object be placed so that it forms an image at 15 cm from the lens? Also calculate the size of the image formed. [Delhi] -Chemistry-10
Last Answer : Answer. hope this helps youu
Description : Write an equation to show the reaction between Plaster of Paris and water -SST 10th
Last Answer : ' solutions : -
Description : Who makes plaster of Paris? -General Knowledge
Last Answer : answer:
Description : Is Plaster of Paris organic or in organic?
Last Answer : Surely Inorganic ✌️
Description : What is Plaster of Paris ?
Last Answer : : Calcium carbonate composed of two atoms of water is called plaster of Paris.
Description : Which of the following mineral is used in cement industry and plaster of paris? A. Marble B. China Clay C. Gypsum D. Fire Clay
Last Answer : ANSWER: C
Description : Which of the following is used for wrapping of fractured bones? (1) White cement (2) White lead (3) Zinc oxide (4) Plaster of Paris
Last Answer : (4) Plaster of Paris Explanation: Plaster of Paris is a plaster made by calcining gypsum. It can be used to impregnate gauze bandages to make a sculpting material called modroc. It is used ... (and sometimes still is) used to make classic plaster orthopedic casts to protect limbs with broken bones.
Description : The chemical name of "Plaster of Paris" commonly used for setting broken bones is – (1) Calcium nitrate (2) Calcium sulphate (3) Calcium carbonate (4) Calcium chloride
Last Answer : (2) Calcium sulphate Explanation: Plaster of Paris is the common name of Calcium Sulphate hemihydrate, with chemical formula: CaSO4.1/2H2O. Plaster of Paris is produced by heating gypsum to about 150°C.
Description : ‘Plaster of paris’ chemically known as (1) Sodium Aluminate (2) Calcium sulphate (3) Spdium bicarbonate (4) Sodium acetate
Last Answer : (2) Calcium sulphate Explanation: Calcium sulphate is a calcium salt that is used for a variety of purposes. It exists in various forms and states of hydration.
Description : 'Plaster of Paris' is made by partial dehydration of – (1) epsom salt (2) gypsum salt (3) blue vitriol (4) green vitriol
Last Answer : (2) gypsum salt Explanation: Plaster is a building material used for coating walls and ceilings. Plaster starts as a dry powder similar to mortar or cement and like those materials it is ... sandpaper. These characteristics make plaster suitable for a finishing, rather than a load-bearing material.
Description : On heating, Gypsum loses certain percentage of its water content and becomes (1) Chalk (2) Calcium sulphate (3) Plaster of Paris (4) a pearl
Last Answer : (3) Plaster of Paris Explanation: Plaster of paris, quick-setting gypsum plaster consisting of a fine white powder (calcium sulfate hemihydrate), which hardens when moistened and allowed to dry.
Description : Setting of plaster of paris involves – (1) dehydration process (2) hydration to form other hydrates (3) oxidation process (4) reduction process
Last Answer : (2) hydration to form other hydrates Explanation: The setting of plaster of Paris takes place by hydration due to the formation of a solid crystalline hydrate and hardening of Plaster of Paris is ... . A slight expansion takes place in the process and heat is evolved. This process is exothermic.
Description : What is formula of plaster of paris?
Last Answer : 2CaSO4.H2O
Description : Which metal is found in ‘plaster of paris’?
Last Answer : Calcium
Description : Melamine formaldehyde resin which has a very high anti tacking properties, is not used for the (A) Electrical insulation purpose (B) Tanning of leather (C) Strengthening of plaster of Paris (D) Decorative laminates
Last Answer : (C) Strengthening of plaster of Paris
Description : Plaster of Paris:
Last Answer : Compound of Calcium. When hydrated, the form is rigid. Blessing for broken bones. Also used for architecture designing(Model designing), Sculpures and for filling purposes in different areas.
Description : Explain the following: (i) Blood group (ii) Short circuit (iii) Short sight (iv) International date line (v) Plaster of Paris
Last Answer : Answers: (i) Blood group A blood type (also called a blood group) is a classification of blood based on the presence or absence of inherited antigenic substances on the surface of red blood ... calcium sulfate hemihydrate, nominally CaSO4 0.5H2O. It is created by heating gypsum to about 150 °C.
Description : Which of the following salts do not have the water of crystalisation? (i) Bleaching Powder (ii) Plaster of Paris (iii) washing soda (iv) Baking soda (a) (ii) and (iv) (b) (i) and (iii) (c) (ii) and (iii) (d) (i) and (iv)
Last Answer : (d) (i) and (iv)
Description : What is the name and chemical formula of the main product formed by heating baking soda. (a) sodium carbonate,Na 2 CO 3 (b) Bleaching powder ,CaOCl 2 (c) sodium chloride,Na Cl (d)Plaster of paris ,CaSO 4 .I/2H 2 O
Last Answer : (a) sodium carbonate,Na 2 CO 3
Description : Gypsum is heated at........temperature to form plaster of paris.(a) 110degree Celsius (b) 120degree Celsius (c) 100degree Celsius (d) 101degree Celsius
Last Answer : (c) 100degree Celsius
Description : At what temperature is gypsum heated to form Plaster of Paris?a) 90°C b) 100°C c) 110°C d) 120°C
Last Answer : b) 100°C
Description : Plaster of Paris is (A) CaSO4 .½H2O (B) Used for setting of broken bones (C) Both (A) and (B) (D) Same as gypsum
Last Answer : (C) Both (A) and (B)
Description : Heating of __________ to 120°C, produces plaster of paris. (A) Blue vitriol (B) Gypsum (C) Calcium silicate (D) Calcium sulphate
Last Answer : (B) Gypsum
Description : Calcination of gypsum produces (A) Plaster of Paris (B) Salt cake (C) Nitre cake (D) Lime
Last Answer : (A) Plaster of Paris
Description : Setting of plaster of Paris is accompanied with (A) Hydration (B) Dehydration (C) Hydrolysis (D) Loss of CO2
Last Answer : (A) Hydration