Answer:
Potassium is an element, with the symbol K
Explanation:
An element is something that cannot be broken down any further, for example, calcium, its Ca.
A compound is when you bond two or more elements. Compounds can be broken down into its original elements, for example, H₂O, it contains two atoms of hydrogen and one atom of oxygen (both hydrogen and oxygen are elements).
<span>PbO
Let's look at each of the 4 compounds and see what's needed.
PbO.
* Oxygen has a valance shell that's missing 2 electrons and wants to get those 2 elections. Lead donates them, so you have a Lead (II) ions. This is a correct choice.
PbCl4
* Chlorine wants to grab 1 electron to fill it's valance shell and Lead donates that election. However, there's 4 chlorine atoms and every one of them wants and electron, and lead is donating all 4 of the desired electrons making the Lead (IV) ion. So this is a bad choice.
Pb2O
* Oxygen still wants 2 electrons and gets them from the lead. But there's 2 lead atoms and each of them donates 1 election making for 2 Lead(I) ions. So this too is a bad choice.
Pb2S
* Sulfur is in the same column of the periodic table as oxygen and if this compound were to exist would have similar properties as Pb2O and would have Lead(I) ions. So this is a bad choice.</span>
Answer:
The pressure in that cylinder = 1.12atm
Explanation:
We use general gas law to calculate it. General gas law is gotten by combining Boyle's law, Charles' law and Avogadro's law. Thus
P = nRT/V
Where n = number of moles
R = the gas constant
T is the Temperature, V is the volume and P is the pressure.
Given: T = 319K, V = 24L, R = 0.0821 L.atm/K.mol
The first step is to find n using
n = mass of O2/molar mass of O2
=32.7/32
=1.0219
Now, using P =nRT/V
P = 1.0219 ×0.0821×319÷24
Therefore P = 1.12atm
You are given
200 grams of H2O(s) at an initial temperature of 0°C. you are also given the
final temperature of water after heating at 65°C. You are required to get the
total amount of heat to melt the sample. The specific heat capacity, cp, of
water is 4.186 J/g-°C. Let us say that T1 = 0°C and T2 = 65°C. The equation for
heat, Q, is
Q = m(cp)(T2-T1)
Q = 200g(4.186
J/g-°C )(65°C - 0°C)
<u>Q =
54,418J</u>
