Question of the day (May 5th) Math olympiad

Q: If the radius of a circle is increased by 100% , the area is correspondingly increased by how many percent ? pi =3.14

Method 1 :Lets say the radius of the circle is 2cm so if it is increased by 100%, it will be 4cm . thus the previous area is 12.56 and the new area is 50.24 thus if we divide this two values the answer will be 4 thus it is 400%. 

OR

Method 2: Since the formula of the area of the circle is Pi(radius)(radius) , and the pi value is constant , we just need to find the difference in values of the square of the radii . Thus it is 4 and 16 so the percentage difference is 400%

Science Question of the Day (5/5/2016)

Hi All, this is the Question of the Day for today.

Classify the items below into elements, compounds and mixtures.

Sodium, Air, Iodine, Carbon Dioxide, Water, Soil



Regards,

Brandon Cheah
ML102

Science Practice Paper (2015 TA)

This is the corrections for science practice paper.

Pg2                                                              Pg3


        


Pg4                                                               Pg5      

                                                         

   

          

Pg 6                                                                           Pg 7

             

Science Worksheet Answers (W5B)

Hi All, this is the corrections for W5B.

1. A
2. B
3. D
4. A
5. C

Structured Questions
1a) Nitrogen, Oxygen
1b) Magnesium, Oxygen
1c) Aluminium, FLOURINE
1d) Carbon, Hydrogen, Oxygen
1e) Carbon, Oxygen
1f) Calcium, Oxygen
1g) Copper, Sulfur

True or False
a) F
b) F
c) T
d) T
e) F
f) (a) A compound can be made up of three or more elements chemically combined (eg. Ammonium Acetate, CH3COONH4)

   (b) *Unsure. Sorry for the inconvenience.

   (e) A compound can not be always be in the same physical state as its elements.

2a) Sodium Chloride
2b) Sodium, Chlorine
2c) Table salt is in the solid form, while chlorine is gaseous in room temperature, and its elements cannot be broken down by heat but salt can be.

3a) Q is produced by chemically combining two substances through heating (chemical method), R decomposes to black solid and gas when heated.

3b) S

4) This is a graphic organizer, thus difficult to put up here. Kindly find out from your buddies/classmates. Thanks.

5a) Iron, Chlorine
5b) 3.
5c) Compound. It consists of 2 elements and it is chemically combined. It also has properties different from its elements.

Math Blue Book Answers and Workings (Pg 37)

Q1:  5x+22-6x-23
= -x-1

Q2:7a-3b+4c-5b-6b
=7a-14b+4c

Q3:-ab-5bc+3ab-6bc
=2ab-11bc

Q4:2(3x+7)
=6x+14

Q5:4u-3(2u-5v)
=15v-2u

Q6:2(2x-3y)-(x+4y)
=4x-6y-x-4y
=3x-10y

Q7:-4(x-2y)+6(x+y)
=-4x+8y+6x+6y
=10x+14y

Q8:a-2[(3b-2a)+a]
=a-2[3b-2a+a]
=a-2[3b-a]
=a-6b+2a
=3a-6b

Q9:4/15 h -2k-5/9(2h-7k)
=4/15 h -2k-10/9h +35/9 k
=-38/45 h + 17/9 k

Q10:0.5a-0.65b-0.25a=2(4ab)
=0.25a-0.65b+8ab

Science Worksheet Answers (W5A)

Hi All, to those that have not caught the answers for W5A, here are the answers below.

1. B (Carbon is NOT a metal as it is not shiny and ductile)

2. C

3. C

4. B

5. A

6. B

7. D

8. C

Structured Questions

2a. No. It can be broken down into simpler substances which is mercury and oxygen by chemical means (heating) but an element cannot.

2b. Oxygen. It will re-light a glowing sprint as it supports combustion.

2c. 2HgO (S) + heat ----> 2Hg (L) + O2 (G)

3a. Li, K, Zn

3b. Shiny when polished and Ductile.

3c. Carbon, Sulfur, Argon, Iodine

3d. i) *Unsure

3d. ii) They have a gradual change of chemical and metallic to non-metallic properties.

3e. Same Group: Li, K (Group I)

      Same Period: Li, C (Period II) K, Zn (Period 4) S, Ar (Period 3)

4. Solids: Carbon, Iodine, Magnesium, Sulfur

    Liquids: Bromine, Mercury

    Neon, Florine, Argon, Hydrogen

5a. Copper Metal

Chemical Formula: Cu

5b. Chlorine Gas

Chemical formula: Cl2

HCL and CL 成语 (26-50)

Hope this list complied by us will help everyone in future tests to come .
Chinese Words and English Meanings for HCL and CL