1) The elements making up the unknown substance almost always include carbon and hydrogen. Oxygen is often involved and nitrogen is involved sometimes. Other elements can be involved, but problems with C and H tend to predominate followed by C, H and O and then by C, H, O and N.
2) We must know the mass of the unknown substance before burning it.
3) All the carbon in the sample winds up as CO2 and all the hydrogen in the sample winds up as H2O.
4) If oxygen is part of the unknown compound, then its oxygen winds up incorporated into the oxides. The mass of oxygen in the sample will almost always be determined by subtraction.
5) Often the N is determined via a second experiment and this introduces a bit of complexity to the problem. Nitrogen dioxide is the usual product when nitrogen is involved. Sometimes the nitrogen product is N2, sometimes NH3.
6) Sometimes the problem asks you for the empirical formula and sometimes for the molecular formula (or both). Two points: (a) you have to know the molar mass to get to the molecular formula and (b) you have to calculate the empirical formla first, even if the question doesn't ask for it. A few lines below is a link that goes to a file that discusses how to go from empirical to molecular formulas.
Answer:
Number 1 is A (I'm not sure but i think it is) and Number 2 is correct (I think)
Explanation:
Answer:
50?
I think but not 100% sure if not lmk
Answer:
a) The volume is 5.236x10⁻¹³L
b) The molarity of a single virus is 1.91x10¹² mol/L
c) The molarity for a 100 virus particles is 1.91x10¹⁴ mol/L
Explanation:
a) Given:
D = diameter of the cell = 10 μm
r = radius = 10/2 = 5 μm
The volume of the spherical cell is equal:
If 1 μm³ = 1x10⁻¹⁵L, then 523.6 μm³ = 5.236x10⁻¹³L
b) The molarity is:
For a single virus within the cell
c) For a 100 virus particles the molarity is:
Answer:
E
Explanation:
Why can a signaling molecule cause different responses in different cells? Different cells have membrane receptors that bind to different sides of the signaling molecule. The transduction process is unique to each cell type; to respond to a signal, different cells require only a similar membrane receptor