Grade

Type of questions

Chemistry Senior High

(4)でどうして4が分母にあるのか分かりません。解説お願いします。

基本例題 2 塩化ナトリウムの結晶 4 塩化ナトリウムの結晶の単位格子を図に示した。 (1)単位格子に含まれるナトリウムイオン Na*, 塩化物イオ ン CI-の数はそれぞれ何個か。 (2) 1個の Na*のすぐそばにある CI- は,中心間距離が何 nm のところに何個か。 (3) 1個のNa*のすぐそばにある Na* は, 中心間距離が何 nm のところに何個か。/2=1.4, 3=1.7 とする。 (4))1 mol の塩化ナトリウムの結晶の体積は何cm° か。 アボガドロ定数=6.0×103/mol, 5.6°=176 とする。 (5)塩化ナトリウムの結晶の密度は何g/cm° か。 Na=23, Cl=35.5 とする。 CI- Nat -0.56nm- 指針 NaClの結晶では, Na* と CI- が接していて, Nat どうし, CI- どうしは接していない。 1 nm=10-° m=10~" cm 解答(1) Na*(●): 4 1 -×12(辺の中心)+1(中心)3D4 (個) 1 CI(O): 8 ×8(頂点)+- ×6(面の中心)=D4 (個) 答 (2) 立方体の中心の Na*に注目すると,上下, 左右,前後に1個ずつの CI- 計6個答 中心間距離は一辺ので で,0.28 nm 答 (3) 立方体の中心の Na*に注目すると, 立方体の各辺の中心の Na* 計 12個 答 中心間距離は面の対角線の で, 0.56 nm×、2×-=0.392 nm=0.39 nm 面の対角線 (4)単位格子(Na*, CI- がそれぞれ4個ずつ)の体積が (0.56 nm)=(5.6×10-° cm)° なので,1 mol (Nat, CLがそれぞれ6.0×103個ずつ)の体積は, 2 2 (5.6×10-8 cm) 6.0×10 4 =26.4 cm°=26 cm° 答 3 58.5g -=2.21… g/cm°=2.2g/cm° 答 3 (5) 密度=質量 より, 体積 26.4 cm 3 基本問題 * =必解

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English Senior High

この文章を並べ替えると答えが 【B→A→E→C→F→D】となるのですが、理由がわかりません💦どなたか大至急教えてください<(_ _)>

大 ( S Read the passage below and answer the questions. 図 There are several reasons behind the growing crisis, The first is waste. About 70 % of our fresh water is used to grow crops. It takes 1,000 tons of water to grow just one ton of wheat. Unfortunately, around 60% of that water is wasted. 回 water 1s our most important natural resource. However, only 2.5% of water on the Earth 18 not salty. Demand for fresh water has risen sharply in the last 50 years, and it is still riSing. Finding answers to these problems may be one of the biggest challenges of the 21st century. 回 Overuse also puts pressure on water supplies, In the USA, 95% of the country's fresh water comes from underground sources. With so much water being used to grow crops and raise livestock, water levels aredropping rapidly. Once used, those supplies are gone forever. D The fresh water crisis is not limited to poor countries. In fact, rich and poor countries from Asia to Europe to North America are facing shortages. It's a growing problem that could soon affect us all. E Second, pollution is another big problem. Many of the world's great rivers are badly polluted and many people depend on the rivers. Their health is affected by the health of the river. Steps are being taken to clean up some rivers, but it can take many years. E In many poor countries around the world, people already live in crisis. More than one billion people have no access to clean water. That leads to millions of deaths every year. By 2025, about 25 African countries may face severe water shortages.

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