Chemistry test paper for grade three?

Reference answer?

20 14.4?

1. Multiple choice questions (***24 points)?

1、D 2、C 3、A 4、D 5、C 6、C 7、C 8、B 9、B 10、B 1 1、C 12、C 13、C 14、D 15、D 16、A 17、C？

18、C？

19、D？

20、B？

2 1、A？

22、C？

23、C？

24、B？

Second, fill in the blanks (***44 points)? 25. (* * *10) 1. (1) ① (2) ③? (3) ② (4)④

(5)⑤ ? (6)⑥ Ⅱ.( 1)② ? (2)① (3)⑤ ? (4)③ 26, (* * * 6 points) (1)2H2O is electrified.

2H2↑+O2↑?

(2) The product of hydrogen atom and oxygen atom is hydrogen and oxygen, which are composed of hydrogen element and oxygen element respectively, and the products are different.

The element type is equal to that of the reactant (3). 0.7?

(4)NaOH and Mg(OH)2?

27.(***4 points) (1) B? ② Reduce the temperature (or increase solute or evaporate solvent) 370 4d? 28.(***5 points) (1)47 (2) Accelerated dissolution.

(3) Magnesium chloride +2 sodium hydroxide →2 sodium chloride+magnesium hydroxide ↓? Mg(OH)2？ CaCO3？ ( 1) (4)A？ b？ (1, 1) 29, (* * * * 6)( 1) Increase the contact area of reactants and speed up the reaction (full reaction)? Carbon dioxide filtration?

(2) heating crystallization? Barium chloride? 1°C？

30. Write (* * * * 6 points) (1) CaCO3+2hcl → CaCl2+H2O+CO2? H2O (2)HCl+AgNO3→HNO3+AgCl↓ (3) Dry carbon dioxide gas cannot be collected (4) Carbon dioxide gas is heavier than air?

(5) Put the dry blue Shi Lei test paper into a gas container, and the test paper will not change color. Equal to 3 1, (* * * 7 points) (1)Zn+H2SO4→ZnSO4+H2↑ A and B (2) dry hydrogen?

(3) The black solid turns red (there are water drops in the tube)? Oxidation? Reduce?

(4)2H2+O2？

light

2H2O

Iii. Experimental questions (***27 points) 32. (* * * 8 points) (1) Long-necked funnel

(2)a B (or d)? Hydrogen is hardly soluble in water (hydrogen is lighter than air)?

(3) Bright blue and purple? S+O2 ignition

SO2？ The concentration of oxygen?

? SO2+2NaOH→Na2SO3+H2O？ 33.(***9 points) (1) This product is colorless and easily soluble in CO2+2NaOH→Na2CO3+H2O (2)CO2 pressure.

(3)Na2CO3 Ca(OH)2？ CaCl2 has bubbles? White precipitate: 34, (* * *10) (1) Cao+H2O → Ca (OH) 2? The reaction process is exothermic? (2) red?

(3) Sodium hydroxide and sodium chloride? ( 1)?

Ca(OH)2+Na2CO3→2NaOH +CaCO3↓？

(4)Na2CO3？ Take a small amount of upper liquid and drop dilute hydrochloric acid? There are bubbles? Or? Ca(OH)2 Take a small amount of the upper feed liquid and add sodium carbonate solution dropwise to produce white precipitate (5) Acid-base neutralization?

(6) decomposition? Replace? ( 1)?

Fourth, the calculation problem (5 points for this question) 35. Solution: (1) m (baso4) = 0.1× 233 = 23.3g? ( 1)?

(2) Let the mass of Na2SO4 participating in the reaction be x?

na2so 4+bacl 2→baso 4↓+2 NaCl( 1) 14233 x 23.3

142233

23.3

X x= 14.2g (1 min) Mass fraction of Na2SO4 in the original solid mixture =

14.2

× 100% 17.5

=83. 1% ( 1)? (3)m (solution) =17.5+80.8+75-23.3 =150g (1).