CHUYÊN ĐỀ TOÁN NỒNG ĐỘ - LẬP HỆ PHƯƠNG ĐẠI SỐ - PHƯƠNG TRÌNH ĐẠI SỐ
CM =
a) Nồng độ mol:
nct
Vdd
b) Nồng độ phần trăm:
C% =
mct
.100%
mdd
Câu 1.
Tìm khối lượng muối ăn để:
a) pha và 400 gam dung dịch NaCl 10% thành dung dịch mới có ndo là 28%.
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b) pha và 600 gam dung dịch NaCl 5% thành dung dịch mới có ndo là 28,75%.
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Câu 2.
Cần bao nhiêu gam nước để pha loãng các dung dịch sau:
a) pha vào 300 gam dung dịch H2SO4 40% thành dung dịch mới 24%.
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a) pha vào 700 gam dung dịch KOH 50% thành dung dịch mới 35%.
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Câu 3.
Có 2 dung dịch muối ăn có ndo lần lượt là 30% và 50%. Cần pha 2 dung dịch trên ntn để được:
a) 500 gam dung dịch mới có ndo là 34%.
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b) 800 gam dung dịch mới có ndo là 45%.
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Câu 4.
Có 2 dung dịch NaOH với ndo chưa biết, thực hiện các thí nghiệm sau
Pha 150 gam dd1 với 100 gam dd2 thu dd mới có ndo là 30%.
Pha 50 gam dd1 với 350 gam dd2 thu dd mới có ndo là 41,875%. Tìm ndo % từng dd ban đầu.
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Câu 5.
Có 2 dung dịch BaCl2 với ndo chưa biết, thực hiện các thí nghiệm sau
Pha 160 gam dd1 với 3400 gam dd2 thu dd mới có ndo là 37,84%.
Pha 300 gam dd1 với 100 gam dd2 thu dd mới có ndo là 21,5%. Tìm ndo % từng dd ban đầu.
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Câu 6.
Có 2 dung dịch H2SO4 có ndo % lần lượt là 14% và 60%. Pha 2 dd đó ntn để được 600 gam dd mới có
ndo 25,5%.
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Câu 7.
Có 2 dung dịch NaClcó ndo % lần lượt là 8% và 45%. Pha 2 dd đó ntn để được 800 gam dd mới có ndo
11,7%.
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