Regents Chemistry

A student measured the melting point of a sample of gallium to be 309 K. Based on Table T, which numerical setup can be used to calculate the student’s percent error?

Which chemical bond is most polar?

• a O–H bond in H₂O

• a S–H bond in H₂S

• a Se–H bond in H₂Se

• a Te–H bond in H₂Te

What is the amount of heat required to melt 43 grams of solid magnesium oxide at its melting point? The heat of fusion is 1.9 x 10³ J/g.

• 2.3 x 10² J

• 4.4 x 10¹ J

• 8.2 x 10⁴ J

• 3.4 x 10⁵ J

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This apparatus is used for which process?

• filtration

• distillation

• chromatography

• electrolysis

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Solid aluminum has a specific heat capacity of 0.90 J/g•K. How many joules of heat are absorbed to raise the temperature of 24.0 grams of aluminum from 300. K to 350. K?

• 22 J

• 45 J

• 1100 J

• 1200 J

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Which sample at STP has the same chemical properties as 10. grams of Al(s) at STP?

• 10. grams of Si(s)

• 10. grams of Na(s)

• 5 grams of Al(s)

• 5 grams of Mg(s)

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What is a potential risk associated with radioactive isotopes?

• biological exposure

• curing of diseases

• industrial measurements

• tracing chemical processes

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Which accurately describes nonmetals?

• Poor conductors of electricity

• Often used in computer parts

• Both malleable and ductile

• Both dull and brittle

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Which properties most accurately describe the element Krypton (Kr)?

• Highly reactive

• Ductile

• Weak conductor of electricity

• Has 8 valence electrons

• Brittle and dull

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Each horizontal row on the periodic table is called a what?

• Group

• Row

• Period

• Family