I think it’s B because I just know
Answer:
0.250 moles of MgO are produced when 0.250 mol of Mg reacts completely with O₂
Explanation:
In first place, the balanced reaction between Mg and O₂ is:
2 Mg + O₂ ⇒ 2 MgO
By stoichiometry of the reaction (that is, the relationship between the amount of reagents and products in a chemical reaction), the following amounts of reactants and products participate in the reaction:
- Mg: 2 moles
- O₂: 1 mole
- MgO: 2 moles
Then you can apply the following rule of three: if by reaction stoichiometry 2 moles of Mg produce 2 moles of MgO, 0.250 moles of Mg, how many moles of MgO will they form?

moles of MgO= 0.250
<u><em>0.250 moles of MgO are produced when 0.250 mol of Mg reacts completely with O₂</em></u>
Answer:
a= <em>In scientific notation</em>
6.96000×10⁵ Km
b =<em>In expanded notation</em>
0.00019 mm
Explanation:
Given data:
Radius of sun = 696000 Km
size of bacterial cell = 1.9 ×10⁻⁴ mm
Radius of sun in scientific notation = ?
Size of bacterial cell in expanded notation = ?
Solution:
Scientific notation is the way to express the large value in short form.
The number in scientific notation have two parts.
. The digits (decimal point will place after first digit)
× 10 ( the power which put the decimal point where it should be)
for example the number 6324.4 in scientific notation will be written as = 6.3244 × 10³
Radius of sun:
696000 Km
<em>In scientific notation</em>
6.96000 × 10⁵ Km
The expanded notation is standard notation of writing the numerical values which is normal way. The numbers are written as they are, without the power of 10.
Size of bacterial cell:
1.9 ×10⁻⁴ mm
<em>In expanded notation</em>
1.9/ 10000 = 0.00019 mm
Answer:
B
Explanation:
"I think my bike is making a scraping noise because the bearings are not lubricated."
The moles of gas in the bottle has been 0.021 mol.
The ideal gas has been given as the gas where there has been negligible amount of interatomic collisions. The ideal gas equation has been given as:

<h3>Computation for the moles of gas</h3>
The gi<em>ve</em>n gas has standard pressure, 
The volume of the gas has been, 
The temperature of the gas has been, 
Substituting the values for the moles of gas, <em>n:</em>
<em />
<em />
The moles of gas in the bottle has been 0.021 mol.
Learn more about ideal gas, here:
brainly.com/question/8711877