Answer:
21
Explanation:
Formula;
Mass number = number of protons + number of neutrons
= 9 + 12
= 21
(a) The temperature goes up by 3⁰C.
(b) There is increase in temperature, so the reaction is exothermic.
(c) Examples of exothermic reaction include, rusting of Iron, burning of coal, reaction of strong acid and water.
(d) Examples of endothermic reaction include, melting solid salts and evaporating liquid water.
<h3>
What is exothermic reaction?</h3>
Exothermic reaction is a type of chemical reaction in which energy is transferred to or from the surroundings.
Examples of exothermic reactions include the following;
- Rusting of Iron
- Burning of Coal
- Reaction of Strong Acid and Water
- Water and Calcium Chloride
<h3>What is endothermic reaction?</h3>
Endothermic reaction is a type of chemical reaction in which energy is absorbed from the surroundings.
Examples of endothermic reactions include the following;
- Melting solid salts.
- Evaporating liquid water, etc
<h3>Change in temperature</h3>
From the increase in temperature from 15⁰C to 23⁰C, we can conclude that the temperature goes up by 3⁰C.
20⁰C - 17⁰C = 23⁰ - 20⁰C = 3⁰C.
Since there is increase in temperature, the reaction is exothermic.
Learn more about exothermic reaction here: brainly.com/question/2924714
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Answer:
poisoning, breathing problems, skin rashes, allergic reactions, allergic sensitisation, cancer, and other health problems from exposure.
Explanation:
many hazardous chemicals are also classified as dangerous goods.
The sulphate solutions came from a recycling LIBs waste cathode materials, which were done by previous research; their content is shown in Table 1 [18]. Sodium carbonate (Na2CO3) was purchased from Nihon Shiyaku Reagent, Tokyo, Japan (NaCO3, 99.8%), for the chemical precipitation. CO2 was purchased from Air Product and Chemical, Taipei, Taiwan (CO2 ≥ 99%), to carry out the hydrogenation–decomposition method. Dowex G26 was obtained from Sigma-Aldrich (St. Louis, MO, USA) and was used as a strong acidic cation exchange resin, to remove impurities. Multi-elements ICP standard solutions were acquired from AccuStandard, New Haven, Connecticut State, USA. The nitric acid (HNO3) and sulfuric acid (H2SO4) were acquired from Sigma-Aldrich (St. Louis, MO, USA) (HNO3 ≥ 65%) (H2SO4 ≥ 98%) The materials were analyzed by energy-dispersive X-ray spectroscopy (EDS; XFlash6110, Bruker, Billerica, MA, USA), X-ray diffraction (XRD; DX-2700, Dangdong City, Liaoning, China), scanning electron microscopy (SEM; S-3000N, Hitachi, Tokyo, Japan), and inductively coupled plasma optical emission spectrometry (ICP-OES; Varian, Vista-MPX, PerkinElmer, Waltham, MA, USA). In order to
Appl. Sci. 2018, 8, 2252 3 of 10
control the hydrogenation temperature and heating rate, a thermostatic bath (XMtd-204;
Answer:
0.9875 mole O₂
Explanation:
Rxn => H₂ + ¹/₂O₂ => H₂O
from above reaction, 1 mol H₂ requires ¹/₂ mol O₂ then 1.975 mol H₂ requires ¹/₂(1.975 mol)O₂ or 0.9875 mol O₂.
