What is 6829 km expressed in scientific notation? a. 6.829 × 100 km b. 6.829 × 103 km c. 6.829 × 102 km d. 6.829 × 10-3 km

your answer is a. the enthalpy of formation for a pure element in its standard state is always positive.

the term hydride is commonly named after binary compounds that hydrogen forms with other elements of the periodic table. hydride compounds in general form with almost any element, except a few noble gases. the trends and properties vary according to the type of intermolecular force that bonds the elements together, the temperature, its molecular masses, and other components. hydrides are classified into three major groups, depending on what elements the hydrogen bonds to. the three major groups are covalent, ionic, and metallic hydrides. formally, hydride is known as the negative ion of a hydrogen, h-, also called a hydride ion. because of this negative charge, hydrides have reducing, or basic properties. its special characteristics will be further discussed.

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