Answer:
(a)

(b)

(c)

Explanation:
(a)
The given compound is silicon tetrabromide. It means that 1 silicon and four bromine atoms are combined to form the molecule.
The chemical formula of silicon tetrabromide is 
(b)
The given compound is disulfur dichloride. It means that 2 sulfur atoms and 2 chlorine atoms are combined to form the molecule.
The chemical formula of disulfur dichloride is 
(c)
The given compound is diphosphorus hexaoxide. It means that 2 phosphorus atoms and 6 oxygen atoms are combined to form the molecule.
The chemical formula of diphosphorus hexaoxide is 
A battery and a banana are the same when considering energy:
A battery when connected to a device produces electro-chemical reactions and contains one or more cells. The same thing can be tried out with fruits also. There are many fruits which can be taken into account. A lemon shows less amount of voltage when seen through a multimeter rather than a banana which shows a higher voltage. This was because of the acid present in the a fully ripped banana. The acid is called ascorbic acid. This acid has a higher pH level than compared to the pH of the citric acid found in lemon.
This shows that a banana plant is not so expensive and reliable for the production of renewable energy and a battery is also inexpensive, reliable and stable.
Answer:
6. 7870 kg/m³ (3 s.f.)
7. 33.4 g (3 s.f.)
8. 12600 kg/m³ (3 s.f.)
Explanation:
6. The SI unit for density is kg/m³. Thus convert the mass to Kg and volume to m³ first.
1 kg= 1000g
1m³= 1 ×10⁶ cm³
Mass of iron bar
= 64.2g
= 64.2 ÷1000 kg
= 0.0642 kg
Volume of iron bar
= 8.16 cm³
= 8.16 ÷ 10⁶


Density of iron bar

= 7870 kg/m³ (3 s.f.)
7.

Mass
= 1.16 ×28.8
= 33.408 g
= 33.4 g (3 s.f.)
8. Volume of brick
= 12 cm³

Mass of brick
= 151 g
= 151 ÷ 1000 kg
= 0.151 kg
Density of brick
= mass ÷ volume

(3 s.f.)
Q1: sort your numbers into numerical order so you can determine the highest and lowest measured values. and then subtract the lowest measured value from the highest measured value. Now determine that the answer is the precision.
Q2: In one meter there are 100 centemeter. Now you got 5.8 miles per hour which will become 580 centemeter per hour. In addition, there are 60 minutes in an hour. Based on what we know, 580 centemeters per hour will and should become 580/60 cm/min