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於學術研究會的年
,我們繫。
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成年頒文明本府及一5
徵
文英級初授教畫圖用
英中會考化學科答案
(續)
王錦釗•
西露 黄金机 售出已册手訂編著:
∵方英换照各笞狮那交站以近一周小肥刻育館 法文鬥难撒介內。之授圖出本投明本正~
set vol. of H. collected
Applying the gas equation
latresTM
五期星
有鯽
日十三月五年九六九一公年八十五國民華中
L
袁汝南堂宗親會
獎汝
大會
劉老禦香浩大學、中文大學、香港工業學院( 該項辦法,4年傅然約用,郭凡該會會貧子女, 升讀大學,經於去年訂有毓法,通化會員週知。 《沿饭)本海安汝南雅尔设社會爲獎助于女
T 可申請助學貸敫
獎助子弟升大學
讀者來函 六號共三影機體會址,做所有真氏宗親入會。 叉核窗於前年鹛得家消大邀西三A四至
(GYM) •
[柳先生 我們是一黨有會考生,我們的
. 盹者希望教署予以解釋
監考員竟不宣佈
數學試題有錯漏
佛烈的,佔全卷一百分的水分,
·昨日常的三共—份有二阻是
有所作。此舉闖不公之至,試問
,一军不平人上,五月廿九日
BOLUTIONS¡
BK.CEB. (English) 1969
Chemistry (Section B)
Suggested answers |
5.(a) (1) Mevzals are electron donare; when they form'
oxidée, they lose electrons and become positively charged ions. The oxides formed are electrovalent compounds.
i
B.E 2Na. + 0:
j: → 2Na+ + 10:1
[:]
Whef a metallic oxide reacts with an acid,
s salt and water only are formed. Electrons) are transferred from the 02- ion in the oxide to the H ion in the acid with the. formation of water molecules.
+
2 [0]
28+ 201
2Ne + 201
Balt
sodium oxide) (base)},
hydrochlorio,
acid
e.8.
water
When non-metals combine with oxygen they form oxides, which are covalent compounds.
20:
XCx
C
X
co2. (molecules)
ione
The oxides of non-metals are molecules. They do not form ions. There are no negatively charged 02- ions to neutralise the H of an acid to form water, (that is, oxides of non-metals cannot transfer electrons, such as metallic oxides do). Hence oxides of non-metals are never baaic...
(ii) Metals, which are more electropositive than hydrogen, are able to transfer electrons to the less electropositive H ion, while they themselves become positively charged ions. The Bions are discharged and become hydrogen molecules.
*.8. Zn + H-S0g = ZnSO
Tonically?
4
94 + H2
Zo
M
Ze
2
‹) 2H* + 29 →→
Zn + 2H→ m
Hydrogen is more electrapositive than all other non-metals, which are therefore unable to transfer electrons to the, hydrogen ionE to discharge them to form hydrogen molecules.
(b)"Concentration of given H2SO4' solution
200 gm. of acid per litre
Weight of acid in 100 ml. of H2SO soln.
We
꼭
芳
760 x
litres]
5.2.11tren
5. (a) 25.UU ml. of given Hola, souSZÖN
= 26.20 ml.0 - NaOH」
Normality of given acid solution
26.20 N
器 25.00
10
-0.1048 N
ws. of crystalline solid acid in 250 ml.
acid solution 1.5 gm.
Concentration of given acid solution
(1.5 × 4) gm of cryst. aolid acid per litre
6.0 gm. of cryst. solid acid oer. titre..
Thus Equivalent wt. of cryst. solid scid
16.0
-
0.1048 57.26
But the acid is dibariR
Molecular wt. of aryag, solid acid
57.26 x2 -114.5.
There are 2 molecules of water of moā.
tion in 1 molecule of the crystalline acid..
Molecular wt. of anhydrous aoid - 114.5 - 36
78.5
i... equivalent wt. of anayarous acid
-
39.25
Hence concentration of anhydrous acid in the given acid solution
39.25 x 0.1048 gm. per litre
- 4.11(2) gm. per litre
(b)
Chlorine.
UNIDOS
Graduated
burettes
chloride
solution
carbon
electrodes
switch
(第七張第二页)
一九六九年中元
物理科
透鏡之焦距
内学生考試題預習
三十)
今將AS其性質相同之B放在一
鄧炳惠 ®
B合於A与物体之間且距A25厘米则 新像因此透鏡组而生成試計算斯像主高及
距離又新像為宴抑虚像.
在一開霍与一首义同振動時相差為8猁秒而
音义之音調较优若音又之频率為256次/秒 声速為340/秒且管口更正量署去不計則 管長須如何改变贻能与音义共鸣。 AB两带電金属球半径分别為及分離 頗遠但以導線連接之
小電量子在距 球
處所受之力為于若七大於丫,但 於西球間之距離求B球之帶電量. 本港
採用之電源為220伏特50次物,没有 家庭装有100瓦特電灯 4 板, 60瓦特電灯 5. 枝試計算比 家庭線路内所用之保險綠之
5小時 月作30日計,每度電0.22元則此 庭每月之電費若干
典
只有電炉两座利用電流通過電阻球而生洲区 下图所示利由 一發電机所供之電光接駁至
電纜之就電阻為25歐姆然後再由甲 联方式接驳王乙炉,甲乙两炒問接驳 電阻亦為 歐姆
電流:10盎
鹅之虚热率
1%,試求發電瓶
腧路電压及功
並求接
Hydrogen
紋電纜所消耗之功率
将两
乙
池与正切電流計、及適 之電阻串联之則正切電流計之指針偏度 若將其中一原電池之接作倒轉接連 $.60° 則電流計之指針偏度為30試比较此二原 電池之電動势
英中會考數學(三)答案
(接第六張第二頁)
(#).
歐陽鋊文·
RD = DC.
AD= DE
Given
ding bisect
ABEC is a ilgram
AC = BE
Givens
cand other
100 1000
* 200 gm.
20 80.
Ng
B2504
4
2
24
98
Wt. of Mg that will react with 98 gm. of pure
H2SO A
24 gm.
Wt. of Mg that will react with 20 gm. of pure
ABAC
Rheostat
ABS BE
Battery
Ju s ABE
AB>BE
Greater side has the greater spjb,
Ion in Solution
NaCl →→→→→→ Na
HO
* Cl
a
Butì
E = a,,
all s
BEIIAC!
(24 x
·) go..
- 4.9 gm.
Wt. of Mp originally used
8.0 go.
Wt. of magnesium left
(8.0 - 4.9) 8./ - 3.1 gm.
Vol. of H. collected at N.T.P. from 90 gm. pure H $0-
Vol. of R2 collected at N.T.P. from 20 cm.
pure H2SO, (V,) 22.4 x
꼭
20 98
litres.
litres
Temperature (T,) = 273*K-,
Pressure (F,) - 760 mm.
If the hydrogen is collected over water at
18°C and 730 mm pressure
Temperature (T2) Pressure (P2). (730
. 712 am,
291 K
18) mm.
There are 2 cations in solution. Both migrate to the CATHODE, where the less electropositive ion, Hion, is delected for discharge, Each H ion discharged receives an electron and becomes a hydrogen atom, which combine with another hydrogen atom to fora
a hydrogen molecule-
สี
H + H → H.
*
There are 2 anions in solution. Both migrate to the ANODE. Although the OH ion is less electro- negative than the CI 1 on the concentration of the C1. ions is far greater than that of the H ions (except in the case of vary dilute solutions) an is able to influence the discharge of ions at the anode. The Cl- ions are thus: discharged in preference.
CIT
→→→→→ CI
Hydrogen gas is therefore.evolved
C1
+ →Ciz
at the cathode.
好 a CAD > < BAD
(b) Given: AD is a chord of
Circle O
AB = BC = CD
To Prove: arc EF >arc AB
Proote Join AO
AO is
OC
E
a radius of
is part of rading of 00
AO SOC
In O OAL. OB is a median
:\AB=BC, given).
by me insult of (a), we ming that
<< BOCE>
AOB
In the same circle, greater angle-standte
on
+
Chlorine gas is therefore evolved at the anode.
Tomorrow, we will take a look at Questione. 2 and 4.
greater, arch
arc. EF > arcTM BE