Bài tập chủ đề 1
Bài 3 trang 46 KHTN 8
<p><strong>Bài tập 3 trang 46 KHTN 8</strong><strong>:</strong> Cho các sơ đồ phản ứng sau:</p>
<p>a) Na + O<sub>2</sub> <span id="MathJax-Element-1-Frame" class="mjx-chtml MathJax_CHTML" style="box-sizing: border-box; display: inline-block; line-height: 0; text-indent: 0px; text-align: left; text-transform: none; font-style: normal; font-weight: normal; font-size: 21.78px; letter-spacing: normal; overflow-wrap: normal; word-spacing: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; border: 0px; margin: 0px; padding: 1px 0px; position: relative;" tabindex="0" role="presentation" data-mathml="<math xmlns="http://www.w3.org/1998/Math/MathML"><mo>&#x2212;</mo><mo>&#x2212;</mo><mo>&#x2212;</mo><mo>&#x2192;</mo></math>"><span id="MJXc-Node-1" class="mjx-math" aria-hidden="true"><span id="MJXc-Node-2" class="mjx-mrow"><span id="MJXc-Node-3" class="mjx-mo"><span class="mjx-char MJXc-TeX-main-R">−</span></span><span id="MJXc-Node-4" class="mjx-mo MJXc-space2"><span class="mjx-char MJXc-TeX-main-R">−</span></span><span id="MJXc-Node-5" class="mjx-mo MJXc-space2"><span class="mjx-char MJXc-TeX-main-R">−</span></span><span id="MJXc-Node-6" class="mjx-mo MJXc-space3"><span class="mjx-char MJXc-TeX-main-R">→</span></span></span></span><span class="MJX_Assistive_MathML" role="presentation"><math xmlns="http://www.w3.org/1998/Math/MathML"><mo>−</mo><mo>−</mo><mo>−</mo><mo>→</mo></math></span></span> Na<sub>2</sub>O</p>
<p>b) P<sub>2</sub>O<sub>5</sub> + H<sub>2</sub>O <span id="MathJax-Element-2-Frame" class="mjx-chtml MathJax_CHTML" style="box-sizing: border-box; display: inline-block; line-height: 0; text-indent: 0px; text-align: left; text-transform: none; font-style: normal; font-weight: normal; font-size: 21.78px; letter-spacing: normal; overflow-wrap: normal; word-spacing: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; border: 0px; margin: 0px; padding: 1px 0px; position: relative;" tabindex="0" role="presentation" data-mathml="<math xmlns="http://www.w3.org/1998/Math/MathML"><mo>&#x2212;</mo><mo>&#x2212;</mo><mo>&#x2212;</mo><mo>&#x2192;</mo></math>"><span id="MJXc-Node-7" class="mjx-math" aria-hidden="true"><span id="MJXc-Node-8" class="mjx-mrow"><span id="MJXc-Node-9" class="mjx-mo"><span class="mjx-char MJXc-TeX-main-R">−</span></span><span id="MJXc-Node-10" class="mjx-mo MJXc-space2"><span class="mjx-char MJXc-TeX-main-R">−</span></span><span id="MJXc-Node-11" class="mjx-mo MJXc-space2"><span class="mjx-char MJXc-TeX-main-R">−</span></span><span id="MJXc-Node-12" class="mjx-mo MJXc-space3"><span class="mjx-char MJXc-TeX-main-R">→</span></span></span></span><span class="MJX_Assistive_MathML" role="presentation"><math xmlns="http://www.w3.org/1998/Math/MathML"><mo>−</mo><mo>−</mo><mo>−</mo><mo>→</mo></math></span></span> H<sub>3</sub>PO<sub>4</sub></p>
<p>c) Fe(OH)<sub>3</sub> <span id="MathJax-Element-3-Frame" class="mjx-chtml MathJax_CHTML" style="box-sizing: border-box; display: inline-block; line-height: 0; text-indent: 0px; text-align: left; text-transform: none; font-style: normal; font-weight: normal; font-size: 21.78px; letter-spacing: normal; overflow-wrap: normal; word-spacing: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; border: 0px; margin: 0px; padding: 1px 0px; position: relative;" tabindex="0" role="presentation" data-mathml="<math xmlns="http://www.w3.org/1998/Math/MathML"><mo>&#x2212;</mo><mo>&#x2212;</mo><mo>&#x2212;</mo><mo>&#x2192;</mo></math>"><span id="MJXc-Node-13" class="mjx-math" aria-hidden="true"><span id="MJXc-Node-14" class="mjx-mrow"><span id="MJXc-Node-15" class="mjx-mo"><span class="mjx-char MJXc-TeX-main-R">−</span></span><span id="MJXc-Node-16" class="mjx-mo MJXc-space2"><span class="mjx-char MJXc-TeX-main-R">−</span></span><span id="MJXc-Node-17" class="mjx-mo MJXc-space2"><span class="mjx-char MJXc-TeX-main-R">−</span></span><span id="MJXc-Node-18" class="mjx-mo MJXc-space3"><span class="mjx-char MJXc-TeX-main-R">→</span></span></span></span><span class="MJX_Assistive_MathML" role="presentation"><math xmlns="http://www.w3.org/1998/Math/MathML"><mo>−</mo><mo>−</mo><mo>−</mo><mo>→</mo></math></span></span>Fe<sub>2</sub>O<sub>3</sub> + H<sub>2</sub>O</p>
<p>d) Na<sub>2</sub>CO<sub>3</sub> + CaCl<sub>2</sub> <span id="MathJax-Element-4-Frame" class="mjx-chtml MathJax_CHTML" style="box-sizing: border-box; display: inline-block; line-height: 0; text-indent: 0px; text-align: left; text-transform: none; font-style: normal; font-weight: normal; font-size: 21.78px; letter-spacing: normal; overflow-wrap: normal; word-spacing: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; border: 0px; margin: 0px; padding: 1px 0px; position: relative;" tabindex="0" role="presentation" data-mathml="<math xmlns="http://www.w3.org/1998/Math/MathML"><mo>&#x2212;</mo><mo>&#x2212;</mo><mo>&#x2212;</mo><mo>&#x2192;</mo></math>"><span id="MJXc-Node-19" class="mjx-math" aria-hidden="true"><span id="MJXc-Node-20" class="mjx-mrow"><span id="MJXc-Node-21" class="mjx-mo"><span class="mjx-char MJXc-TeX-main-R">−</span></span><span id="MJXc-Node-22" class="mjx-mo MJXc-space2"><span class="mjx-char MJXc-TeX-main-R">−</span></span><span id="MJXc-Node-23" class="mjx-mo MJXc-space2"><span class="mjx-char MJXc-TeX-main-R">−</span></span><span id="MJXc-Node-24" class="mjx-mo MJXc-space3"><span class="mjx-char MJXc-TeX-main-R">→</span></span></span></span><span class="MJX_Assistive_MathML" role="presentation"><math xmlns="http://www.w3.org/1998/Math/MathML"><mo>−</mo><mo>−</mo><mo>−</mo><mo>→</mo></math></span></span> CaCO<sub>3</sub>↓ + NaCl</p>
<p>Lập phương trình hoá học và cho biết tỉ lệ số nguyên tử/ số phân tử của các chất trong mỗi phản ứng.</p>
<p><strong>Trả lời:</strong></p>
<p>a) 4Na + O<sub>2</sub> → 2Na<sub>2</sub>O</p>
<p>Tỉ lệ:</p>
<p>Số nguyên tử Na : Số phân tử O<sub>2</sub> : Số phân tử Na<sub>2</sub>O = 4 : 1 : 2.</p>
<p>b) P<sub>2</sub>O<sub>5</sub> + 3H<sub>2</sub>O → 2H<sub>3</sub>PO<sub>4</sub></p>
<p>Tỉ lệ:</p>
<p>Số phân tử P<sub>2</sub>O<sub>5</sub> : Số phân tử H<sub>2</sub>O : Số phân tử H<sub>3</sub>PO<sub>4</sub> = 1 : 3 : 2.</p>
<p>c) 2Fe(OH)<sub>3</sub> → Fe<sub>2</sub>O<sub>3</sub> + 3H<sub>2</sub>O</p>
Xem lời giải bài tập khác cùng bài