ANSWER ALL QUESTIONS SECTION A :

OBJECTIVES

1. If 10cm3 of hydrogen gas were sparked with 20cm3 of oxygen. Calculate the volume of residual gas after cooling. a. 25cm3 of O2. b. 5cm3 of O2 c.15cm3 of O2. d.10cm3
2. These are adverse effects of chemistry except a. pollution b. population. c. corrosion d. drug abuse
3.The addition of water to calcium oxide is a a. physical change b. chemical change c. formation of mixture d. endothermic reaction
4. 'All pure samples of a particular chemical compound contain similar elements combined in the same proportion by mass' This is the law of a. conservation of mass b. definite proportion c. multiple proportion d. partial pressure
5. Which of these is odd? a. diamond. b. graphite c. bronze d. coal
6. The ability of an element to exist in two or more physical states but maintaining the same chemical characteristics is calleda. isotopy b. isomerism c. allotropy d. buffer
7. Kipp's apparatus is an equipment for preparing intermittent supply of gases by reacting a. liquid and gas b. Liquid with solid c. solid with gas d. liquid with liquid
8.Producer gas has a low heating power because it contains morea. carbon dioxide than oxygen b. nitrogen than carbon monoxide c. hydrogen than oxygen d. nitrogen than hydrogen
9. Temporary hardness of water is caused bya. CaCO3 b. Na2CO3. c. Ca(HCO3)2 d. coal tar
10.The choice of fractional distillation as a separation techniques is based on closeof constituents. a. density. b. melting point c. solubility d. moiling point

SUBJECTIVE

1.The PH of a 0.005m hydrogen tetraoxosulphate vi acid is
2.Potash alum KAl(SO4)2.12H2O is an example of salt
3. A method that can separate solvent from its solution is
4. When a gaseous substance transforms directly into solid state the process is called
5. The aqueous liquid released as one of the products of destructive distillation of coal
6. The crystalline structure of graphite is in shape
7. The solid form of carbon (IV)oxide is called
8.When carbon (IV) oxide is bubbled into slaked lime the solution turns
9.The petroleum fraction used in surfacing of road is
10. Incomplete combustion in engines is a major sources of

h let me think

in cartography, a contour line (often just called a "contour") joins points of equal elevation (height) above a given level, such as mean sea level. a contour map is a map illustrated with contour lines, for example a topographic map, which thus shows valleys and hills, and the steepness or gentleness of slopes.

explanation:

pre-sliced bread is a relatively recent development in baking technology. previous to that, it was always sold in a bakery in daily-made contiguous loaves with no wrapping, and was moderately perishable, usually being used with a day or two (which is why every bakery had a discounted “day-old” bread table.) therefore, pre-sliced bread would grow stale quickly. the hard crust provided a protective layer, and once the exposed dry slice left from the previous cut was removed, the interior was still soft.

what keeps bread soft is the moisture retained in the crumb (the light spongy part that’s not crust). the reason the crust develops is the surface of the dough gets exposed to hot dry air during baking which browns the outer layer and seals it, preventing all the moisture from escaping the dough. longer exposure to air will also eventually cause your bread to lose flavor and become stale.

people were used to cutting slices as they needed them and storing bread in a specially-made wooden or metal breadbox or pail with a lid to preserve it longer, but the first automatically sliced commercial loaves were produced on july 6, 1928, in chillicothe, missouri, using a machine invented by otto rohwedder, an iowa-born, missouri-based jeweler.[1] pre-sliced bread would indeed dry out, were it not for another 20th century technology: the plastic bag. bread could now be pre-sliced, and if the enclosing bag remains sealed as much as possible, the bread will remain soft and fresh for longer than if sitting unwrapped on a shelf or enclosed in a bread box that is not air-tight. sealed packaging meant bread could also be sold on store shelves and eliminate frequent trips to a bakery.

sealing bread in a plastic bag had another effect: the moisture in the loaf will re-distribute into the crust and soften it, which is sometimes more pleasing in a sandwich - especially for children whose teeth might not yet be strong enough to tear through a hard crust. a homemade loaf of bread can be sealed in a bag overnight and the crust will become soft like store-bought sandwich bread.

these were novel changes in how bread was produced and sold, which led to the coining of the phrase “the greatest thing since sliced bread.”