如何判斷答案

範例 22 下列哪一種金屬最宜作光電池的陰極面? (A)Na (B)Li (C)Cs (D)Mg。 解:(C) THE 北頭張貼日 *** 【71 私醫】 PR 1730 13 30

為什麼苯甲酸的熔點比乙醯苯胺高？ 它們形成的氫鍵有什麼不一樣嗎？

求問這題怎麼解

練演2-3.將10克的銅片放入硝酸銀溶液中,等銅片表面附有一層金屬銀後取出, 洗淨、乾燥,然後稱得其重量為 12 克,則在銅片上析出的銀重量約為多少克? (原子量:Ag=108,Cu=63.5) (A)7.6 (B)4.8 (C)2.8 (D) 6.4。

想請問這題🙏，有點看不懂圖三的公式是從何而來，卡住了

EXAMPLE 21.11 FIELD OF A UNIFORMLY CHARGED DISK A nonconducting disk of radius R has a uniform positive surface charge density o. Find the electric field at a point along the axis of the disk a distance x from its center. Assume that x is positive. SOLUTION IDENTIFY and SET UP: Figure 21.25 shows the situation. We rep- resent the charge distribution as a collection of concentric rings of charge dQ. In Example 21.9 we obtained Eq. (21.8) for the field on the axis of a single uniformly charged ring, so all we need do here is integrate the contributions of our rings. EXECUTE: A typical ring has charge dQ, inner radius r, and outer radius r + dr. Its area is approximately equal to its width dr times its circumference 2πr, or dA = 2πr dr. The charge per unit area is σ = dQ/dA, so the charge of the ring is do = o da = 2πor dr. We use dQ in place of Q in Eq. (21.8), the expression for the field due to a ring that we found in Example 21.9, and replace the ring 21.25 Our sketch for this problem. Idr dQ X P dEx dEx radius a with r. Then the field component dEx at point P due to this ring is 1 2πσrx dr 4π€0 (x² + ²)3/2 SOLUTION Continued

求解，拜託🙏🏻

氯酸鉀(KCO3)加熱分解出KCI與O2 (1) 當取0.8 mol的KCIO,可產生O2多少mol? (2) 標準狀態下,產生3.36 L的O2,同時有多少克的KCI生成? 2KClO3 → 2KCl + 3O2 (9) 標準狀態 : 0°C, 1 atm ■ MW: KCl3 (122.5), KCI (74.5), O₂ (32)

為什麼此題答案為D

-8 範例7 設氯有二種同位素,分別爲C1,C1,且已知在自然界中,Cl佔 75 %, 37 Cl佔 25 %,試回答下列各問題: (1)在質譜儀中,Cl+2,Cl+,C咕離子可產生幾條譜線? (A)1條(B)3 條(C)5條(D)7 條(E)9 條。

為什麼氫氣的價數（n)是2不是1呢 謝謝回答

32.某金屬a克,完全溶解於鹽酸時,產生6莫耳的氫氣及M離子。下列 1245 何者爲此金屬之原子量? OKYO-MO) 2a 26 (B) 3b $2(A)- 30601 a 。 26 (D) 6 (C) 36 a+b a-b (5) OR(A) 港聞港連鎖,然 L

想請問有人可以幫我解答下面這三題有機化學的反應嗎？

(a) (c) OH Dou 4 ch H Br (e) Il Juille 1. CH₂1 2. Ag₂O, H₂O 3. heat 1. KH, reflux 2. H₂O CH3 NaOMe, McOH

想問這幾題 抱歉沒有解答 真的不太會連續迫近法 謝謝大家

B. [4 pts) Calculate the pH of a 0.02 M H₂A solution. If this H₂A with Kaf100 and Kaz= 4.0 x 10-² -5 C. (5 pts) Calculate the [H*] in 2.0 x 10¹5 M HA, if this HA with K₂ = 4 x 10-6. [Successive approximation should be needed). Q 3, B. [show calculation). Consider a weak acid HA with a Ką value of 4 x 10-6. Calculate the pH of a solution that contains 4.0 x 10-6 M HA and 4.0 x 10-6 M NaA. [Successive approximation should be needed). Show your Successive approximation

求這2題詳解🙏🙏🙏

2. 3. (C)水深10 公尺處有一密閉 金屬球殼,半徑為 20 公分;其內 空氣為一大氣壓力.請問球表面 因內外壓力差異所受之力為:(A) 4926 N; (B) 9852 N; (C) 49260 N; (D) 98520 N. (A)同上題,若將球殼內部抽 真空,球表面因內外壓力差異所 受之力變為何?已知大氣壓力為 101325 N/m². (A) 100192 N; (B) 10020 N; (C) 202650N;(D)不變