Sec 2 Sci Sun 9-11am by https://padlet.com/brightculture/sb160qhre0zu0lm1 en-us 2024-12-18 06:33:58 UTC 2025-12-14 02:07:11 UTC hello@padlet.com bernicetay221 https://padlet.com/brightculture/sb160qhre0zu0lm1/wish/3279382002 2025-01-03 15:35:46 UTC https://padlet.com/brightculture/sb160qhre0zu0lm1/wish/3279382002 https://padlet.com/brightculture/sb160qhre0zu0lm1/wish/3296017081

  • New substances are formed. 2. The change is often irreversible.

    • (a) (ii)

    Answer: Iron + Oxygen → Iron oxide

    (b) (i)

    1. Alkalis contain hydroxide ions.

    2. The formula for the hydroxide ion is OH⁻.

    Answer: Name: Hydroxide ion; Formula: OH⁻

    (b) (ii)

    1. Test: Bubble the gas through limewater (calcium hydroxide solution)

    2. Observation: The limewater will turn milky or cloudy if carbon dioxide is present.

    Answer: Test: Bubble the gas through limewater. Observation: Limewater turns milky/cloudy.

    (b) (iii)

    Answer: Litmus

    (b) (iv)

    1. Carefully add a few drops of a suitable indicator (e.g., litmus) to separate samples of the acid and alkali.

    2. Observe the color change. Litmus turns red in acid and blue in alkali. Alternatively, a universal indicator could be used to determine the pH.

    Answer: Add a few drops of litmus solution to separate samples. Acid will turn litmus red, and alkali will turn litmus blue.

    (a) (i)


    ]]>     2025-01-19 02:42:27 UTC https://padlet.com/brightculture/sb160qhre0zu0lm1/wish/3296017081     https://padlet.com/brightculture/sb160qhre0zu0lm1/wish/3703347472 2025-11-30 01:39:03 UTC https://padlet.com/brightculture/sb160qhre0zu0lm1/wish/3703347472 Stephanie stephaniehtoo161011 https://padlet.com/brightculture/sb160qhre0zu0lm1/wish/3703347716 Zn + 2HCL-> ZnCl2 +H2

    ]]>     2025-11-30 01:40:00 UTC https://padlet.com/brightculture/sb160qhre0zu0lm1/wish/3703347716     Rui Xuan teo_rui_xuan_2 https://padlet.com/brightculture/sb160qhre0zu0lm1/wish/3703348066 2025-11-30 01:41:22 UTC https://padlet.com/brightculture/sb160qhre0zu0lm1/wish/3703348066 Rui Xuan teo_rui_xuan_2 https://padlet.com/brightculture/sb160qhre0zu0lm1/wish/3703350381 2025-11-30 01:48:56 UTC https://padlet.com/brightculture/sb160qhre0zu0lm1/wish/3703350381 https://padlet.com/brightculture/sb160qhre0zu0lm1/wish/3703351334 2025-11-30 01:52:23 UTC https://padlet.com/brightculture/sb160qhre0zu0lm1/wish/3703351334 stephanie stephaniehtoo161011 https://padlet.com/brightculture/sb160qhre0zu0lm1/wish/3703352209 NaOH(aq) + HNO3 (aq) -> NaNO3 (aq) + H2O (l)

    ]]>     2025-11-30 01:55:03 UTC https://padlet.com/brightculture/sb160qhre0zu0lm1/wish/3703352209     stephaniehtoo161011 https://padlet.com/brightculture/sb160qhre0zu0lm1/wish/3703353242 CaCO3(l) + H2SO4 (aq) -> CaSO4 (l) + CO2 (g) +H2O (l)

    ]]>     2025-11-30 01:57:48 UTC https://padlet.com/brightculture/sb160qhre0zu0lm1/wish/3703353242     teo_rui_xuan_2 https://padlet.com/brightculture/sb160qhre0zu0lm1/wish/3703354459 2025-11-30 02:02:15 UTC https://padlet.com/brightculture/sb160qhre0zu0lm1/wish/3703354459 https://padlet.com/brightculture/sb160qhre0zu0lm1/wish/3703356496 2025-11-30 02:09:10 UTC https://padlet.com/brightculture/sb160qhre0zu0lm1/wish/3703356496 teo_rui_xuan_2 https://padlet.com/brightculture/sb160qhre0zu0lm1/wish/3703358820 2025-11-30 02:17:10 UTC https://padlet.com/brightculture/sb160qhre0zu0lm1/wish/3703358820 stephaniehtoo161011 https://padlet.com/brightculture/sb160qhre0zu0lm1/wish/3703361023 1a. 2NaOH (aq) + H2SO4 (aq) -> Na2SO4 (aq) + 2 H2O (l)

    2a. CaCl2 (aq) + 2AgNO3 (aq) -> 2AgCl (s) + Ca(NO3)2 (aq)

    ]]>     2025-11-30 02:24:09 UTC https://padlet.com/brightculture/sb160qhre0zu0lm1/wish/3703361023     https://padlet.com/brightculture/sb160qhre0zu0lm1/wish/3703361229 2025-11-30 02:24:56 UTC https://padlet.com/brightculture/sb160qhre0zu0lm1/wish/3703361229 darren https://padlet.com/brightculture/sb160qhre0zu0lm1/wish/3706458430 2025-12-02 07:32:36 UTC https://padlet.com/brightculture/sb160qhre0zu0lm1/wish/3706458430 Veldis https://padlet.com/brightculture/sb160qhre0zu0lm1/wish/3706462095 2025-12-02 07:35:39 UTC https://padlet.com/brightculture/sb160qhre0zu0lm1/wish/3706462095 darren https://padlet.com/brightculture/sb160qhre0zu0lm1/wish/3706499680 2025-12-02 08:07:50 UTC https://padlet.com/brightculture/sb160qhre0zu0lm1/wish/3706499680 Veldis https://padlet.com/brightculture/sb160qhre0zu0lm1/wish/3706504958 2025-12-02 08:13:08 UTC https://padlet.com/brightculture/sb160qhre0zu0lm1/wish/3706504958 teo_rui_xuan_2 https://padlet.com/brightculture/sb160qhre0zu0lm1/wish/3712955574 2025-12-07 01:42:24 UTC https://padlet.com/brightculture/sb160qhre0zu0lm1/wish/3712955574 teo_rui_xuan_2 https://padlet.com/brightculture/sb160qhre0zu0lm1/wish/3712958225 2025-12-07 01:51:58 UTC https://padlet.com/brightculture/sb160qhre0zu0lm1/wish/3712958225 teo_rui_xuan_2 https://padlet.com/brightculture/sb160qhre0zu0lm1/wish/3712962564 2025-12-07 02:08:17 UTC https://padlet.com/brightculture/sb160qhre0zu0lm1/wish/3712962564 teo_rui_xuan_2 https://padlet.com/brightculture/sb160qhre0zu0lm1/wish/3721590475 2025-12-14 01:42:41 UTC https://padlet.com/brightculture/sb160qhre0zu0lm1/wish/3721590475 CCl4 teo_rui_xuan_2 https://padlet.com/brightculture/sb160qhre0zu0lm1/wish/3721592387 2025-12-14 01:52:41 UTC https://padlet.com/brightculture/sb160qhre0zu0lm1/wish/3721592387 teo_rui_xuan_2 https://padlet.com/brightculture/sb160qhre0zu0lm1/wish/3721595536 2025-12-14 02:07:09 UTC https://padlet.com/brightculture/sb160qhre0zu0lm1/wish/3721595536