All categories

2 years ago

The number of moles of mgo produced when 0.20 mole of o2 reacts completely is ________. 2mg + o2 → 2mgo

1 answer:

5 0

From the balanced equation o the reaction:
2Mg + O2 → 2MgO
from this equation we can see that:
1 mole of O2 gives → 2 moles of MgO
So 0.2 moles of O2 will give → ????
So the number of moles of MgO = (0.2 mol O2 )* (2 mol MgO) / (1 mol of O2)
= 0.4

You might be interested in

Describe how you would prepare approximately 2 l of 0.050 0 m boric acid, b(oh)3.

Elenna [48]

The given concentration of boric acid = 0.0500 M

Required volume of the solution = 2 L

Molarity is the moles of solute present per liter solution. So 0.0500 M boric acid has 0.0500 mol boric acid present in 1 L solution.

Calculating the moles of 0.0500 M boric acid present in 2 L solution:

$2 L * \frac{0.0500 mol B(OH)_{3} }{1 L} = 0.100 mol B(OH)_{3}$

Converting moles of boric acid to mass:

$0.100 mol B(OH)_{3} * \frac{61.83 g}{mol B(OH)_{3}} = 6.183 g$

Therefore, 6.183 g boric acid when dissolved and made up to 2 L with distilled water gives 0.0500 M solution.

5 0

2 years ago

As Jesse's hybrid accelerates to pass a car on the highway, he notices that his gas mileage drops from 40 miles per gallon to 15

e-lub [12.9K]

The most likely explanation for this observation is C. his car has turned on more pistons to provide the extra energy needed to accelerate.

When cruising, hybrid cars are able to employ electrical energy to drive the car. Moreover, even if a vehicle is not a hybrid, a greater amount of fuel is consumed when one accelerates because the vehicle has to generate a force larger than the force of air resistance in order for it to accelerate. This increased demand of force reduces the vehicle's fuel economy.

7 0

2 years ago

Read 2 more answers

A 100.0mL bubble of hot gases at 225 C and 1.80 atm escapes from an active volcano, what is the new volume of the bubble outside

Inessa05 [86]

<h3>Answer:</h3>

112.08 mL

<h3>Explanation:</h3>

From the question we are given;

Initial volume, V1 = 100.0 mL
Initial temperature, T1 = 225°C, but K = °C + 273.15

thus, T1 = 498.15 K

Initial pressure, P1 = 1.80 atm
Final temperature , T2 = -25°C

= 248.15 K

Final pressure, P2 = 0.80 atm

We are required to calculate the new volume of the gases;

According to the combined gas law equation;

$\frac{P1V1}{T1}=\frac{P2V2}{T2}$

Rearranging the formula;

$V2=\frac{P1V1T2}{T1P2}$

Therefore;

$V2=\frac{(1.80atm)(100mL)(248.15K)}{(498.15K)(0.80atm)}$

$V2=112.08mL$

Therefore, the new volume of the gas is 112.08 mL

8 0

2 years ago

When an athlete gets hurt they apply sometimes an instant cold pack to the injury. The instant cold pack works by mixing two che

NeX [460]

Answer:

The evidence showing that there is a chemical reaction taking place is the instantaneous temperature drop once the cold pack is shaken.

Explanation:

When an athlete applies a cold pack to the injury, they shake it before, mixing the water and <em>ammonium-nitrate fertilizer</em> inside the cold pack. This mixing is an endothermic reaction, which means it absorbs heat. In turn, the temperature falls to 35 F for around 10 minutes.

3 0

2 years ago

If you find that the hydrogen alpha line in a star’s spectrum occurs at a wavelength of 656.45 nm, what is the star’s approximat

Paladinen [302]

Answer:

The answer to the question is

The star’s approximate radial velocity is 68.52 km/s

Explanation:

To solve the

The formula is

$\frac{\lambda-\lambda_{rw}}{\lambda_{rw}} = \frac{v_r}{c}$ where