Answer:
32.25 J
Explanation:
Heat, H = ?
Mass, m = 5g = 5 / 1000 = 0.005 Kg
Initial Temperature = 75.0° C
Final Temperature = 25.0° C
Temperature change, ΔT = Final - Initial = 50° C
Specific heat capacity of lead, C = 129 (J/kg°C)
The relationship between these quantities is given by the equation
H = mCΔT
H = 0.005 * 129 * 50
H = 32.25 J
Answer:
179.87 g/mol
Explanation:
First you need to determine the number of each elements in the molecule. This information comes from the molecular formula.
Ze(NO3)2 tells us that there is 1 Ze atom and 2 NO3 anions per molecule. each NO3 anion will have 1 nitrogen and 3 oxygens. Due to that, one molecule of Ze(NO3)2 will have 1 atom of Ze, 2 atoms of nitrogen (N), and 6 atoms of oxygen (O).
Next you need to add all of the individual atom's molar masses to get the over all molar masses. The molar masses of each element is in the question but it can also be found on the periodic table.
molar mass of Ze(NO3)2 = 55.85g/mol + (14.01g/mol*2) + (16.00g/mol*6)
molar mass of Ze(NO3)2 = 179.87 g/mol
I hope this helps.
Answer: 1. C. polar covalent: electrons shared between silicon and sulfur but attracted more to the sulfur
2. B) 
3. B) Fluorine
Explanation:
1. A polar covalent bond is defined as the bond which is formed when there is a difference of electronegativities between the atoms.
Electronegativity difference = electronegativity of sulphur- electronegativity of silicon = 2.5 -1.8 = 0.7
Thus as electronegativity difference is less than 1.7 , the cond is polar covalent and as electronegativity of sulphur is more , the electrons will be more towards sulphur.
2. A molecular compound is usually composed of two or more nonmetal elements. Example:
Ionic compound is formed by the transfer of electrons from metals to non metals. Example: 
, 
and 
3. For formation of a neutral ionic compound, the charges on cation and anion must be balanced. The cation is formed by loss of electrons by metals and anions are formed by gain of electrons by non metals.
Here K is having an oxidation state of +1 and as the compound formed is KZ, the oxidation state of non metallic element Z should be -1. Thus the element Z is flourine which exists as diatomic gas 
CH₄(g) + 3 Cl₂(g) → CHCl₃(g) + 3 HCl(g)
From the equation we notice that 1 mole of methane produces 1 mole of chloroform:
16 g Methane → 119.38 g Chloroform
? g Methane → 37.5 g Chloroform
by cross multiplication:
= (16 * 37.5) / 119.38 = 5.0 g methane
Sorry for the scribbles lol
