Answer is: selenium (Se).
1) electron configuration: ₃₄Se 1s²2s²2p⁶3s²3p⁶3d¹⁰4s²4sp⁴.
2) ₃₃As 1s²2s²2p⁶3s²3p⁶3d¹⁰4s²4sp³.
3) ₃₆Kr 1s²2s²2p⁶3s²3p⁶3d¹⁰4s²4sp⁶.
4) ₃₁Ga 1s²2s²2p⁶3s²3p⁶3d¹⁰4s²4sp¹.
Valence electrons of selenium are 4s²4sp⁴.
Answer:
Hydrogen peroxide should be stored in
1) a cool environment
2) with amber bottles away from sunlight
3) with little drops of sodium phosphate
Explanation:
It has been confirmed that heat and light aids in the decomposition of hydrogen peroxide according to the equation; 2H2O2→2 H2O + O2.
This means that hydrogen peroxide must be stored in a cool place. This will reduce its rate of decomposition. Secondly, it should be stored in amber bottles away from light since light also aids in its decomposition.
Thirdly, drops of sodium phosphate may be added to prevent its catalytic decomposition during storage.
Answer : The volume of solution will be 2.96 liters.
Explanation :
Molarity : It is defined as the number of moles of solute present in one liter of volume of solution.
Formula used :

In this question, the solute is NaF.
Now put all the given values in this formula, we get:



Therefore, the volume of solution will be 2.96 liters.
To answer the problem given:
|0.53−4.0| / 4.0 * 100%
= 3.47 / 4.0 * 100%
= 87%
The maximum theoretical percent recovery from the
crystallization of 4.0 g of acetanilide from 100 ml of water is 87%. I
am hoping that this answer has satisfied your query and it will be able to help
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Answer:
70.0°C
Explanation:
We are given;
- Amount of heat generated by propane as 104.6 kJ or 104600 Joules
- Mass of water is 500 g
- Initial temperature as 20.0 ° C
We are required to determine the final temperature of water;
Taking the initial temperature is x°C
We know that the specific heat of water is 4.18 J/g°C
Quantity of heat = Mass × specific heat × change in temperature
In this case;
Change in temp =(x-20)° C
Therefore;
104600 J = 500 g × 4.18 J/g°C × (x-20)
104600 J = 2090x -41800
146400 = 2090 x
x = 70.0479
=70.0 °C
Thus, the final temperature of water is 70.0°C