The equation to calculate Density is Mass / Volume. You are given that the density is 5.45 and the mass is 65; 5.45 = 65 / v. So v = 65 / 5.45; v = 11.93 mL (or if you want your answer to consider significant figures, v = 12 mL).
There are essentially 5 states of matter-
1) Solid
2) Liquid
3) Gas
4) Plasma
5) Bose-Einstein Condensate
Plasma comprises of positive and negatively charged particles that are formed in extremely high temperature conditions. A characteristic of plasma is that it is not dense enough. The ions tend to be far apart, which makes them to spread out and imparts compressibility.
Ans B)
To solve this questions you first need to find the number of moles of barium phosphate you have. The molar mass of barium phosphate is 601.93g/mol.
24.4/601.83 = 0.0402 moles barium phosphate
Then you need to use avagadro’s number, 6.022 x 10^23, which is the number of molecules or formula units in a mole.
6.022 x 10^23 * 0.0402 = 2.42 x 10^22 formula units
Alkanes are hydrocarbons that only contain single bonds in them. A carbon can bond with up to 4 atoms, even with another carbon atom. So, in a C-C bond, 3 more H atoms can bond to each of the C atom. Generally, the chemical formula for alkanes is CₓH₂ₓ₊₂. So for butane, there are 4 C atoms. The corresponding H atoms are 2(4) + 2 = 10. That's why it's chemical formula is C₄H₁₀.