16. Metals have a structure containing delocalised electrons, meaning they can conduct electricity as they allow movement of charged particles. 17. groups of elements (columns) react in the same way, but depending on whether they group tends to lose or gain electrons the reactivity can increase or decrease when going down the group (column) 18. O2 is non polar as there is no difference in electronegativity between two oxygen atoms (they are the same). CO2 is non polar, it has polar bonds (O is more electronegative than C) but as it is symmetrical there is no polarity in the molecule. 19. Water is polar as the lone pairs on the O repel the delta + H groups so that the HOH angle is around 109deg, so water molecules create polar interactions which each other. These polar interactions require energy to break, so water has a higher boiling point than other small molecules which don't have these interactions. 20. The metal used is tough, and the horseshoe is usually heated meaning the metal will act slightly more viscous (closer to liquid). This means it can be moulded better, and then when its cooled it will become stronger and more brittle. 21. Well N2 + H2 --> NH3, by the haber process, so nitrogen:hydrogen ratio is 1:3. But what they want you to say is that nitrogen has 5 electrons and hydrogen has 1 and you're aiming for eight so you need N (5) + 3 Hs (3*1=3) to make NH3 (8 electrons around N) 22. Na and H, as this reduces the valence shell number and therefore reduces the energy state of the atom 23. Ar, its very stable as its octet is filled, meaning to fill or empty its octet it would have to lose or gain 8 electrons which is extremely hard 24. Oxygen, as it would accept the electrons donated by the 2 Na atoms, and fill its octet while emptying both the Na's 25. N2 and O2 are both covalently bonded, Oxygen forms a double bond to itself like this O=O and nitrogen forms a triple bond to itself like this N<span>≡N </span><span>Hope that helps :) and make sure you learn this, it'll come back and bite you when you need it for a test</span>
Answer:
Explanation:
193.02 times 9.55 it's going to be 1843.341
9.55= 191.20 milli
Answer:
Empirical formula is C₄H₁₀O
Explanation:
Values for C, H and O are determined as centesimal composition.
64.80 g of C in 100g of compound
13.62g of H in 100 g of compound
21.58 g of O in 100 g of compound.
We convert the mass to moles:
64.80 g . 1mol/ 12g = 5.4 moles of C
13.62 g . 1 mol /1g = 13.62 moles of H
21.58 g . 1 mol/16g = 1.35 moles of O
We pick the lowest value and we divide:
5.4 moles of C / 1.35 = 4 C
13.62 moles of H / 1.35 = 10 H
1.35 moles of O / 1.35 = 1 O
Empirical formula is C₄H₁₀O, it can be the diethyl ether.
We confirm, the excersise is well done.
Molar mass = 74g/mol
74 g of compound we have (12 . 4)g of C
In 100 g of compound we may have (100 . 48) / 74 = 64.8 g
Answer:
40.5 g/mL
Explanation:
Density is a measure of a substance's mass over its volume.
d = m/v
Therefore d = 255.15g/6.3mL = 40.5 g/mL
Answer:
The mass methane (CH4) required is, 25 grams (option C)
Explanation:
Mass of oxygen gas = 100 g
Molar mass of oxygen gas = 32 g/mole
Molar mass of methane gas = 16 g/mole
<u>Step 1:</u> Balance the reaction
2O2 + CH4 → CO2 + 2H2O
<u>Step 2:</u> Calculate the moles of O2:
Moles O2 = mass of O2 / Molar mass of o2
Moles O2 = 100g / (32g/mole) = 3,125 moles
⇒From the balanced reaction we conclude that 2 moles of O2 react with 1 mole of CH4
⇒ So, 3.125 moles of O2 react with 3.125/2 = 1.563 moles of CH4
<u>Step 3:</u> Calculate the mass of CH4:
Mass of CH4 = moles of CH4 x Molar mass of CH4
Mass of CH4 = 1.563 moles / (16g/ moles) = 25.008 grams CH4
