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.)
 
        
             
        
        
        
In a high-mass star, hydrogen fusion occurs via the CNO (Carbon-Nitrogen-Oxygen) cycle.
According to the life cycle of a star, there are three main phases in the life of a star: The initial phase (a quick phase), short phase or supergiant phase and death phase or supernova explosion.
the CNO cycle means Carbon-Nitrogen-Oxygen cycle and this process tale place during main sequence phase.
In this phase, hydrogen fuses into helium as a result of six different reaction taking place inside a star.
The first step of the sequence begins when the nucleus of carbon 12 isotope emits gamma rays after capturing a proton and produces nitrogen-13.
This whole cycle is known as stellar nucleosynthesis.
If you need to learn more about Carbon-Nitrogen Cycle click here:
brainly.com/question/13022835
#SPJ4
 
 
        
             
        
        
        
N = given mass/ molar mass.
n = number of moles
given mass = 2.47 g
molar mass = 197 g/mol
n = 2.47 / 197 
n = 0.01253 moles.
I'm sure you wanted to ask more than this. Just put some comments in. I can do the same.
        
             
        
        
        
Answer:
<h3>The answer is 2.16 moles</h3>
Explanation:
To find the number of moles in a substance given it's number of entities we use the formula

where n is the number of moles 
N is the number of entities
L is the Avogadro's constant which is 
6.02 × 10²³ entities
From the question we have

We have the final answer as
<h3>2.16 moles</h3>
Hope this helps you