Question

5. The temperature in an orchard is 0°C. If a farmer sprays 10.0 kg of water at 20°C around the fruit trees and the water cools, then freezes at 0°C, how many kilojoules of energy are released? How does this energy affect the orchard temperature? 6. Classify each of the following as element, compound, homogeneous or heterogeneous mixture: Gasoline, bubbly champagne, coffee with lemon juice, cola drink, sulfur, helium, mercury. Isopropyl alcohol ("rubbing alcohol"), table sugar, common salt, "plaster cast, steel, pewter, ethylene glycol (auto coolant), silicon. 7. Give the group, family, period and atomic number Strontium, scandium, polonium, astatine, phosphorus, boron, potassium, platinum, curium, selenium. f the following elements: 8. List the elements in the following compounds: Lye (sodium hydroxide), baking soda (sodium bicarbonate), Epsom salt (magnesium sulfate), table sugar, table salt, antifreeze (ethylene glycol), hydrogen peroxide, "dry ice", vinegar (acetic acid), auto battery acid. [You must first write the correct chemical formulas before listing the elements (names or symbols).]

Answer 1

5) Here, an exothermic reaction is produced which is calculated by

E= M*C*T

where E= Energy transferred in joules

M= Mass of substance in Kg

C= Specific Heat Capacity (water=4200J/kg)

T= Temperature in ^$\degree$ C

E= 10*4200*20

= 840000 joules of heat is released to maintain 0^$\degree$C

6) Element: Sulfur, Helium, Mercury, Silicon

Compound: Common Salt, table sugar, isopropyl alcohol, ethylene glycol

Homogeneous: Gasoline,

Heterogeneous: Coffee with lemon juice, Bubbly champagne, Coca Cola, plaster cast, steel, pewter

7)

	Group	Family	Period	Atomic number
Strontium	2 (IIa)	Alkaline earth metal	5	38
Scandium	3	Transition element	4	21
Polonium	16	Metalloids	6	84
Astatine	17	Halogens	6	85
Phosphorus	15 (VA)	Non-metal	3	15
Boron	13	Metalloids	2	5
Potassium	1	Alkali metal	4	19
Platinum	10	Transition element	6	78
Curium	3	Transition element	7	96
Selenium	16	Non-metal	4	34

8)

Compound	Chemical formulas	Elements
Lye	NaOH	Na, O, H
Baking Soda	NaHCO3	NA, H, C, O
Epsom Salt	MgSO4	Mg, S, O
Table Sugar	C12H22O11	C, H, O
Table Salt	NaCl	Na, Cl
Antifreeze	C2H6O2	C, H, O
Hydrogen peroxide	H2O2	H, O
Dry ice	CO2	C, O
Vinegar	CH3COOH	C, H, O
Auto battery acid	H2SO4	H, S