What dose it mean if and element has no subscript in a chemical formula

Great amounts of electromagnetic energy from our sun and other bodies in space travel through space. which is a logical conclusion about these electromagnetic waves? their energy must be very their frequency must be very low these waves can travel without a medium they only travel through a vacuum of space

What is the mass of 2.00 l of an intravenous glucose solution with a density of 1.15 g/ml?

What is the molecular weight of copper