For a given reaction with DHorxnequal to 200 kJ, which statement is correct? ( )
A. The reaction is endothermic and the container of the reaction feels cool
B. The reaction is endothermic and the container of the reaction feels warm
C. The reaction is exothermic and the container of the reaction feels cool
D. The reaction is exothermic and the container of the reaction feels warm
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The DHorxn for which reaction is a standard enthalpy of formation? ( )
A. SnCl4(l) ® SnCl2(s) + Cl2(g)
B. SnCl2(l) ® Sn(s) + Cl2(g)
C. 2Cl2(g) + O2(g) ® 2Cl2O(g)
D. Cl2(g) + H2O(l) ® HCl(aq) + HOCl(aq)
Which one has similar properties to phosphorus ( )?
A. silicon (Si)
B. carbon (C)
C. oxygen (O)
D. arsenic (As)
Air within a container is ( )
A. heterogeneous mixture
B. homogeneous mixture
C. an element
D. a compound
How many significant figures are there in 0.004010? ( )
A. 6
B. 3
C. 7
D. 4
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