買四第張四第日八十月二十年丑癸层复
夏僑榮
1974中學會考試題預習專欄:
BAUER L4
化學科(课程甲)(九) 林景源
CHEMISTRY (9)
Surgested answer for last week: L. The statement "sulphur dioxide
contains its own volume of oxygen. expreases the fact that if sulphur ds burned in oxygen, the volume of sulphur dioxide produced is. eanal to the volume of oxygen used in forming it, provided that. both volumes are meaured at the same temperature and pressure. This can be shown experimentally by using the apparatus shown in the diagram.
Some sulphur is placed in bha dry tube, and dry oxygen is passed: through the whole apparatua for a few minutes. The clip is closed and mercury poured into the teno- meter. To make the pressure in t tube atmospheric, the clig is momentarily released. The sulphur is then heated with a small flame It burus until all the oxygen is used up. After the invitial move- ment due to the expansion of the
the me oury returns to Ite original position. Thus the volume of ga aous oxide formed must be aqual; to the volume of oxygen that went to form it. Henou sulphur dioxide contains its own volume of oxygen.
SO
2
Solid.1 Vol.1Vol.
Avoyadro's principle allova is to substitute "molecules" for "volume 1 molecule of sulphur dioxide therefore contains 1 molacula of oxygen or, as oxygen ie diatonic, 2. atoms off oxygen, In other words the formula of the gas is Skog: To find the value of x it is necessary to determine experiment- ally the relative density of the gau, ie, the weight of a certain volume of the gas divided by the
weight of an equal volume of hydxogeny both volumes being measured at the same temperature and pressure. By using for instan-
ce Regnault's asthed it is found that the relative density of Bulphur, dioxids 18:32.
The moleoul ar weight of any gan je twice its relative density, a relationship which can be deuced
from Arogadro's principle. The
·molecular weight of aulphur dioxide is therefore 64. As the formula has been found to be Sxû and the
2 atomic weights of sulphur and oxygen are known to be 32 and 16; it follows that
32x+32 64
The formula of sulphur dioxide::
30
Carbon Relative- 15.8
weight
Sulphur
84.2
Holative 15.8.
no.of atoms 12
Divided.
.32 1.32
by smallest
1.32422.63
粥。
The empirical formula is CS,
The Vol. formula is
However
(C5)
ite M. H.- 2xV.D. =
.1
The molecular formula is CS2
7. Carbon dioxide and
onate
A. "Carbon dioxide Préparation::
Carbon dioxide is usually prepared in the laboratory by the action of dilute hydrochloric acid on marble
CaCO3 + 2HCL®
→→CaCl2
The reaction is, however, unsat- iefactory if the metallic salt formed a insoluble in water or
WAH KIU YAT PO
nearly so. For example, marble and dilute sulphuric acid effervesce. for a few seconde; then the action: stops because the spring soluble calcium sulphate forms a coating.. -on the marble and the acid has no
furthér contact with the marble. Usually collected over warm water or, by downward delivery
Properties:
Carbon dioxide is a colourlesst Cas with only a slight smell. It is mederately soluble Ln water, It 8
22). At
denser than air (yn C. it can be:
temperature below
easily liquifled under increased pressure. When the liquid is allow ed to escape into the air, it solid ified to "carbon dioxide snow!, - whfch sublimes without melting at 78°C.
Chemical:
a. Action of water
The solution is slightly acidic;
it does not turn blue litmus solution: fully red
+ CO2
The acid is dibasic; consequently. it. can form two sets of salts, the normal carbonates and the bicarbonates.
b. Stability of carbon dioxide.
Carbon dioxide is very stable to heat; it shows no apreciable
decomposition below 1300°C, and
at 1450 C its degree of dissoci ation is only about
If previouslying-003;
magnesium
buris in carbon dioxide:for a short time with a soluttering
flame) producing white particles
of its oxide and black carbon particles.
CO
+
2MgO C
Sodium and potassium are burnt
in the gas, if previously ignited
forming their carbonates and cart
Na + 3002
with heated carbon: oxide is formed
C
200
mone
d. With alkalis to give salts or
acidic salte,
2. State four commercial uses
:carbon d
咁僑嗤
四期星
日十月一年四七九一层公年三十六國民華中有教僑華
3某些固体溶货自洛流中話時,有一
3將鸭汤液静置,固体粒子阶沉降纷
定量的水和洛變作分子性的结合而成的体
体倾去,则固体粒子可以与流体分離,這種
法
Apparatus:was set up to find the
percentage of carbon dioxide in/
2-metallic carbonate using. tha)拆出,這些含水的晶体梅作
'action of acid :on the carbonate;
The following readings were
taken ::
Weight of aonaratus with. acid
and without carbonate 67.93 km
Weight-of apparatus with: acid
and with carbonate - 76.33.
Wes ght of apparatus, after reactior =74.95 89.
Calculate the percentage of. carbor dioxide in the carbonate.
Make a labelled sketch of the
apristatus just before the reartior takes place.
1874 中學會考試題預習專欄 堅道書院主稱
化學科(課程乙)(九)王兆文
測驗之
時間,两小時
AJ B. 懸滑液(水合物
2. 乾燥劑 E過飽和结晶
1胆礬(硫酸铜)含若干国分子之话 7將洛液加热使溶制氢化内与国体制 晶水
SA. 2
「之濬览分開,這種分離方法捐作
DIO E Oh.
10傳望(Mj80-760)合水之半 @硫酸钠体长.
国分子结晶水
A.69.27% 8.51.27% 0.53.4%
D. 从7.37% E. 52.77%
壓力成正比,此棒
一般氢体的溶解度,与其说面所受的 1
定律
结晶体直空教中的逐漸失去,回温度增加,人多国体和液体的溶解
度都
载体的溶解度邸
A再结晶 0欣泌 水解 6風化
2溶解度曲线是用以表示 A.溶解度和壓力之關係
3.溶解度和湿度之間体
甲部
全答
上選擇題(15%)
1鹼6灰是
A. 氧化钙及鍋之混合物
3.氫氧化鈣及釣之混合物.
c. 氧化钙及氧化釣之混合物:
1. 氧化钙及氫氧化纳之混合物.
E. 氫氧化鈣及氫氧化鈉之混合物
NaOH
Na2CO2 + 420
CO
3氢氧化钙通铸 A.生石灰
With lime water:
When carbon dioxide is bubbed int lime water; the latter turi milky insoluble carbonate,
CO2 + Ca(OH)2 CaCO3+H2O M
Excess CO, is passed the milkine ness will disappear.
Caco +
H20
Ca(HCO3
8.鹼石灰 c熟石灰 D.石灰乳.6.3个土
1.溶解度和洛制之開後
E溶解度和濃度之関係
3下列何者不是常用之乾燥劑!
A.濃硫酸
C.五氧化二钒 生氯化鈣
3.立氧化二磷
生石灰 D.
@下列各物質,何者最易昇華!
8.6%
A紅磷
A. 22.64
D.碗
4下列五種化合物,最不易潮解的 是
3背特硬水最方便之軟化法是將之A氯化钙 B.硫酸钙
B.硫酸钙c.碘化钾
A.過滤、煮沸
C.加入明礬 点加入胧光
1.加入碳酸鈉.
n硝酸銀E.氫氧化鈉.
(五)填-
題:(25%)
4硬水不適用於说谁是因
7 將生石灰加水之反應能放出大量
的热,比变化誨為
This is a test for carbon dioxide A.釣,錢之狗酸鹽子洛挖水
Osea:
In the solvay process for the manufacture of sodium carbonate and bicarbonate.
2.In the manufacture of aerated water, which are formed by forcing. carbon dioxide under -pressure into solutions of
various essences.
In the fire extinguishers.
These often contain sodium bie: carbonate solution and sulphur: ic acid. When, mixed by invers
ion or passing a plunger the tro.produce carbon dioxide
The oressure of the gas forces
out a atrean of liquid:
2NaHCO ; H SO
Refrigeration:
+ H2O + CO2
The sclid carbon dioxide (dry ico) is used in the preservat- ion of ice-cream during trans sport or sale and, with ether, as a refrigerating mixture.
questions for this week:
1. Describe the reaction of this
gas with (a) burning taper,(b): magnesium and (c) sndium hydrox- ide solution.
Why does the proportion of caris bon dioxide in the atmosphere remain approximately constant?
B.据老子洛玲硬水♡
C. 硬水含身不深物资 D. 既包是脂酸鈉 4.無上確答案
1两性硬水的軟化是在此硬水中加入
A克死3.熱破 (碳酸鈉
D. 奇性戀王.生灰乳
6蔗糖溶解於水而成糖水時则
A. 蔗糖是溶劑,水是洛览能水是溶液
B.蔗糖是浴货,水是溶液,糖水是溶劑
2石灰水呈性文稿,可用來檢 驗
石灰水能生成色沉殿.
3碳酸钙受强熱會分解成.
知
国天然水中含.
赫作
精作
皙将硬水;
永久硬水。
e.蔗糖是溶货,水是溶劑,糖水是溶液 5工菜上所用之硬水軟化法是使硬
蔗糖是溶劑,水是溶液,糖水是客
E.蔗糖是溶液,水是溶劑,按水是瘩赞
3.上硫化碳
7下列那一種不是常用的溶劑! 4.酒精 C.四氯化碳 E. 牛乳
汽油
水滤過
3在温度子变下提路议中可析出资 的溶液,持念_ 浴议。
10過量之工氧化碳通入澄清之灰水中, 然後將灰水煲滚,所見在水颜色之 【轉賣債次應為
乙部(607)選答回题.
7解精溶解度的定義
如何测得一枪览在集温度下之溶
2把在100°C時飽和的氣化鉀 高设200元,冷却到20°C時,多少克 氯化鉀結晶玉米?
(2)在其温度下:50克的飽和溶液 今月10元某種溶览,在此温度下,這種物 梦的溶解度是多少?
3完成及平衡下列方程式。
(ay Mg (HCO;), + NaOH.
(C) C2SO + Na2 CO
(d) CaCO3 + HCk
Les CACH CO2), + Ca(OH),
(6)舉出易風化的物質之種!
(5)舉出結晶体之種!
()舉出常用溶剂立柱!
(4)舉出港解度曲线之用處?
氯酸钾溶解度為70°°C将32克.
6溶液静直後,並無固体粒子沉降用 20°C時8元,氯化钾溶解度為10°C
_法也不能把它們分開。
持48元,20°C持球克,今南30克 氯酸钾与20克氯化钾混合物。以
7將胆響之結晶直试管中加盟則 見晶体由藍色轉為色粉末,因
70°C之水100克洛解之,有否同体 .刺留!將溶液冷却至20°C有何沉
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