Chemical hourglass

Ola zimachitikira ndi kusintha amene zotsatira (mwachitsanzo, kusintha mtundu) sizimaonekera nthawi yomweyo, koma patapita nthawi pambuyo kusakaniza reagents. Palinso machitidwe omwe amakulolani kuti muwone zotsatira zake kangapo. Poyerekeza ndi "chemical clock" amatha kutchedwa "chemical hourglass". Ma reagents a chimodzi mwazoyeserera sizovuta kupeza.

Pakuyesa tidzagwiritsa ntchito magnesium oxide, MgO, 3-4% hydrochloric acid, HCl_aq (moyikira asidi, kuchepetsedwa ndi madzi 1: 9) kapena vinyo wosasa (6-10% yothetsera asidi asidi CH₃COOO). Ngati tilibe magnesium oxide, mankhwala othana ndi acidity ndi kutentha pamtima adzalowa m'malo mwake - chimodzi mwazosakaniza ndi magnesium hydroxide (MgO imasandulika pawiri ngati izi zimachitika).

Udindo wa kusintha mtundu pa anachita bromthymol buluu - chizindikirocho chimakhala chachikasu mu njira ya acidic komanso pafupifupi buluu.

Kwa galasi 100 cm³ Thirani supuni 1-2 za magnesium oxide (chithunzi 1) kapena kutsanulira pafupifupi 10 cm³ kukonzekera munali magnesium hydroxide. Kenako onjezerani 20-30 cm.³ madzi (chithunzi 2) ndi kuwonjezera madontho ochepa a chizindikiro (chithunzi 3). Sakanizani zomwe zili mugalasi lamtundu wa buluu (chithunzi 4) ndiyeno kutsanulira masentimita angapo³ asidi acid (chithunzi 5). Kusakaniza mu galasi kumasanduka chikasu (chithunzi 6), koma patapita kanthawi amasanduka buluu (chithunzi 7). Powonjezera gawo lina la yankho la asidi, timawonanso kusintha kwa mtundu (chithunzi 8 ndi 9). Kuzungulira kungathe kubwerezedwa kangapo.

Zotsatira zotsatirazi zidachitika mu beaker:

1. Magnesium oxide imachita ndi madzi kupanga hydroxide ya chitsulo ichi:

MgO + N₂O → Mg(OH)₂

Zotsatira zake sizisungunuka bwino m'madzi (pafupifupi 0,01 g pa 1 dm³), koma ndi maziko amphamvu ndipo kuchuluka kwa ayoni a hydroxide ndikokwanira kukongoletsa chizindikiro.

2. Zomwe magnesium hydroxide ndi kuwonjezera kwa hydrochloric acid:

mg (OH)₂ + 2HCl → MgCl₂ + 2H₂O

kumabweretsa neutralization ya onse Mg (OH) kusungunuka m'madzi₂. Kuchuluka kwa HCl_aq amasintha chilengedwe kukhala acidic, zomwe tingathe kuziwona mwa kusintha mtundu wa chizindikiro kukhala wachikasu.

3. Mbali ina ya magnesium oxide imachita ndi madzi (equation 1.ndi kuletsa asidi ochulukirapo (equation 2.). Njira yothetsera imakhala yamchere kachiwiri ndipo chizindikirocho chimasanduka buluu. Kuzungulira kumabwerezedwa.

Kusintha kwachidziwitso ndikusintha chizindikiro chomwe chimagwiritsidwa ntchito, chomwe chimatsogolera kumitundu yosiyanasiyana. Pakuyesa kwachiwiri, m'malo mwa bromthymol buluu, tidzagwiritsa ntchito phenolphthalein (yopanda mtundu mu njira ya asidi, rasipiberi mu njira ya alkaline). Timakonzekera kuyimitsidwa kwa magnesium oxide m'madzi (omwe amatchedwa mkaka wa magnesia), monga momwe adayesera kale. Onjezani madontho angapo a phenolphthalein solution (chithunzi 10) ndikusonkhezera zomwe zili mugalasi. Pambuyo powonjezerapo ochepa³ hydrochloric acid (chithunzi 11) kusakaniza kumakhala kopanda mtundu (chithunzi 12). Mwa kuyambitsa zomwe zili mkati nthawi zonse, munthu amatha kuwona mosinthana: kusintha kwa mtundu kukhala pinki, ndipo mutatha kuwonjezera gawo la asidi, kusinthika kwa zomwe zili m'chombocho (Chithunzi 13, 14, 15).

Zochitazo zimachitika mofanana ndi momwe zimakhalira poyamba. Kumbali ina, kugwiritsa ntchito chizindikiro chosiyana kumabweretsa zotsatira zamitundu yosiyanasiyana. Pafupifupi chizindikiro chilichonse cha pH chingagwiritsidwe ntchito poyesa.

Chemical Hourglass Gawo I:

Chemical Hourglass Gawo I

Chemical Hourglass Gawo II:

Chemical Hourglass Gawo XNUMX