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What is the percentage by mass of silicon (si) in iron aluminum silicate (fe3al2(sio4)3)?

Nonpoint source pollution is difficult to control because it

Pinene is an unsaturated hydrocarbon found in pine resin. if pinene has m+ = 136 and contains 1 double bond(s) and 2 ring(s); what is its molecular formula? enter the formula in the form ch first, then all other atoms in alphabetical order; do not use subscripts. the formula is case-sensitive