1s²
Explanation:
The predicted electron configuration of Helium 1s².
Helium is an element with atomic number of 2. it is located on the last group on the periodic table.
- Electron distribution into the energy levels or sublevels of atoms can be shown using electronic configurations.
Here, the two electrons in Helium fills the first energy level with s-sublevel first.
The maximum number of electrons in the sub-level is 2: this gives the 1s² configuration.
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Answer:
The specific heat of the alloy 
Explanation:
Mass of an alloy 
= 25 gm
Initial temperature 
= 100°c = 373 K
Mass of water 
= 90 gm
Initial temperature of water 
= 25.32 °c = 298.32 K
Final temperature 
= 27.18 °c = 300.18 K
From energy balance equation
Heat lost by alloy = Heat gain by water
[ - ] = 
( - )
25 × × ( 373 - 300.18 ) = 90 × 4.2 (300.18 - 298.32)
This is the specific heat of the alloy.
Balanced Equation is
4H2SiCl2+4H2O → H8Si4O4 + 8HCl
Answer:
Mg S2 O3
Explanation:
.691 g of Mg is .284 mole
1.84 g of S is .5739 mole
1.365 g of O is .8531 mole you can see the ratio is ~ 1 :2 :3
Mg S2 O3
Answer:
The time taken for the cross to become invisible decreases.
Explanation:
We know that one of the factors affecting the rate of reaction is the concentration of reactants. From the collision theory, we know that the higher the concentration of reactants, the greater the possibility of effective collision between reactants leading ultimately to an increase in the rate of reaction. Increase in the rate of reaction implies that the reaction takes a shorter time to reach completion.
In the case of the reaction shown in the question, the point when the reaction is completed is observed by the time take for the cross mark to become invisible. If we look at the given data closely, we will notice that the volume of acid was held constant, the volume of thiosulphate was increased gradually while the volume of water was decreased accordingly. This implies that the concentration of the reactants was increased. Decreasing the volume of water increases reactant concentration.
As explained above, increase in reactant concentration increases the rate of reaction. Hence, the rate of reaction of the acid and thiosulphate increases as reactant concentration increases and the cross mark becomes invisible faster. This implies that in the last column for time taken for the cross to become invisible, the values of time decreases steadily as concentration of reactants increases.
