H3PO4 и H2SiO3 дайте сравнительную характеристику физических и химических свойств. Превидите уравнения реакции
Физ св-ва
H3PO4 - бесцветные кристаллы, хорошо растворима в воде, водный 85% раствор - бесцветная сиропообразная жидкость, без цвета и запаха.
Хим. св -ва
Вступает в реакцию с оксидами:
2H3PO4 + 3Na2O = 2Na3PO4 + 3H2O
С основаниями:
H3PO4 + 3KOH = K3PO4 + 3H2O
С солями:
H3PO4 + 3AgNO3 = Ag3PO4 + 3HNO3
Физ. св - ва:
слабая, нерастворимая в воде кислота.
Хим. св - ва
В воде не растворяется.
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2.She is ill,...........................?
3.They are in the fifth form,..............................?
4.You are a pupil,........................?
5.He is ten,.........................?
6.He isn"t hungry,...........................?
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8.They aren"t difficult,..................................?
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15.The apple is testerthan the pear,..................?
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20.Maths is difficult,..............?
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22.She was at the zoo last Suturday,.....................?
23.They wery busy,..............................?
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31.it is cold,.......................?
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34.There is book on the desk,.......................?
35.There is blackboard there,........................?
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37.It is your exercise-book,.............................?
38.The cake is on the table,...........................?
39.There is a cake on the table,...................?
40.The ball is under the table,.......................?
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