Filtration. A filter is a porous barrier. Heterogeneous means it's a visible mixture, i.e large enough particles to see.
Atomic mass silicon = 28.085 u
1 mol Si ---------------- 28.085 g
? ------------------------ 245 g
245 x 1 / 28.085 =><span> 8.72 mol</span>
<span>answer A</span>
The answer is <span>increasing the surface area of Fe(s) and increasing the concentration of HCl(aq).
the rate of reaction can be increased if the interaction between the reactants in better. by increasing the surface area of a solid, such as Fe, you make more possible each molecule of Fe to interact with HCl. Also, by increasing the concentration of HCl, it mean there is more molecule of HCl to interact with Fe.</span>
Answer:
Most similar - Lithium
Least similar - Phosphorus
Explanation:
Rubidium is an element in group 1A of the periodic table. It is a metal and forms an ionic compound with chlorine. The formula of the compound is RbCl.
If we look at the options, Lithium is also a group 1A element and forms an ionic compound with chlorine having the formula LiCl which is very much similar to RbCl chemically.
Phosphorus is a nonmetal. Its compounds with chlorine, PCl3 and PCl5 are covalent and does not resemble RbCl in any way.
1) The metal which reduces the other compound is the one higher in the reactivity. So in this case it is 
.
2) The substance which brings about reduction while itself getting oxidised (that is losing electrons) is called a reducing agent. Here, $\mathrm{Zn}$ is the reducing agent and reduces Cobalt Oxide to Cobalt while itself getting oxidised to Zinc oxide.
