Answer: for an object or gas or liquid to float in another there must be a difference in density
Explanation:
Helium has a density of 0.18 kg/m³ and air has a density of 1.29 kg/m^³. If a balloon is filled with helium it will float in air due to density differences
Archimedes' principle states that the upward buoyant force that is exerted on a body immersed in a fluid, whether fully or partially submerged, is equal to the weight of the fluid that the body displaces
<span>The molar heat of solution of NaOH is -445,100 J/mol. To compute much heat (in J) will be released if 40.00 g of NaOH are dissolved in water, we first convert the given grams of NaOH to moles of NaOH, and use the given molar heat of solution to compute for the energy. (Using dimensional analysis):
40 g NaOH x (1 mol NaOH/ 40 g NaOH) x (-445100 J / 1 mol NaOH) = -445100 J of energy.</span>
Yes the answer is true as long as it combines physically and not chemically to form the new substance which would then called a mixture.
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solution;
Rhizoferrin is a member of a new class of siderophores (microbial iron transport compounds) based on carboxylate and hydroxy donor groups rather than the commonly encountered hydroxamates and catecholates. We have studied the coordination chemistry of rhizoferrin (Rf), as a representative of this group, with Fe(3+), Rh(3+), Cr(3+), Al(3+), Ga(3+), VO(2+), and Cu(2+). The metal complexes have been studied by UV-vis, CD, NMR, and EPR spectroscopies and mass spectrometry. The formation constants for the iron complex have also been measured and yield a log K(LFe) of 25.3. The Rh and Cr rhizoferrin complexes are unusual in that they appear to adopt a chirality about the metal center that is the opposite of the native iron analog. Several of the alternative metal ion complexes are found to have biological activity toward Morganella morganii in a plate type assay.