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sertanlavr [38]

2 years ago

13

An atom of elements x has one more shell of electrons than an atom of beryllium,but h are s one less valence electron then beryl

lium.which element is element X?

1 answer:

Ilia_Sergeevich [38]2 years ago

5 0

Element X is sodium.

If there is one more shell of electrons, then this means it is one period below.

Since there is one less valence electron, it is one group to the left.

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Enter your answer in the provided box. an aqueous solution containing 10 g of an optically pure substance was diluted to 500 ml

sladkih [1.3K]

Answer:

[α] = -77.5° / $\frac{\textup{dm-g}}{\textup{mL}}$

Explanation:

Given;

Mass of optically pure substance in the solution = 10 g

Volume of water = 500 mL

Length of the polarimeter, l = 20 cm = 20 × 0.1 dm = 2 dm

measured rotation = - 3.10°

Now,

The specific rotation ( [α] ) is given as:

[α] = $\frac{\alpha}{c\times l}$

here,

α is the measured rotation = -3.10°

c is the concentration

or

c = $\frac{\textup{Mass of optically pure substance in the solution}}{\textup{Volume of water}}$

or

c = $\frac{10}{500}$

or

c = 0.02 g/mL

on substituting the values, we get

[α] = $\frac{-3.10^o}{0.02\times2}$

or

[α] = -77.5° / $\frac{\textup{dm-g}}{\textup{mL}}$

7 0

3 years ago

Choose the phrase that best describes h20

Kitty [74]

I need the answers or a picture to help

6 0

3 years ago

In this reaction: Mg (s) + I₂ (s) → MgI₂ (s) If 2.68 moles of Mg react with 3.56 moles of I₂, and 1.76 moles of MgI₂ form, what

melomori [17]

Answer:

$Y=65.7\%$

Explanation:

Hello,

In this case, for the given chemical reaction, we first identify the limiting reactant by noticing that due to the 1:1 mole ratio for magnesium to iodine the reacting moles must the same, nevertheless, there are only 2.68 moles of magnesium versus 3.56 moles of iodine, for that reason, magnesium is the limiting reactant, so the theoretical turns out:

$n_{MgI_2}^{theoretical}=2.68molMg*\frac{1molMgI_2}{1molMg} =2.68molMgI_2$

Thus, we compute the percent yield as:

$Y=\frac{n_{MgI_2}^{real}}{n_{MgI_2}^{theoretical}} *100\%=\frac{1.76mol}{2.68mol} *100\%\\\\Y=65.7\%$

Best regards.

8 0

3 years ago

A 40.0 L balloon is filled with air at sea level (1 atm @ 25 oC). It is then tied to a rock and thrown into a cold lake and it s

velikii [3]

To solve this question you need to calculate the number of the gas molecule. The calculation would be:
PV=nRT
n=PV/RT
n= 1 atm * 40 L/ (0.082 L atm mol-1K-<span>1 * 298.15K)
</span>n= 1.636 moles

The volume at bottom of the lake would be:
PV=nRT
V= nRT/P
V= (1.636 mol * 277.15K* 0.082 L atm mol-1K-1 )/ 11 atm= <span>3.38 L</span>

8 0

3 years ago

Is water made of plant cells or animal cells<br> •plant<br> •animals<br> •niether

Pepsi [2]

Answer:

i think niether

Explanation:

5 0

2 years ago