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3 years ago

Which list of elements consists of metalloids, only?

Chemistry

2 answers:

scoray [572]3 years ago

6 0

Answer:

D) Si, Ge, As

Explanation:

A complete list of metalloids are boron (B), silicon (Si), germanium (Ge), arsenic (As), antimony (Sb), tellurium (Te), polonium (Po) and astatine (At)

rewona [7]3 years ago

4 0

Answer: D

Explanation: Boron (B), Silicon (Si), Germanium (Ge), Arsenic (As), Antimony (Sb), Tellurium (Te) and, Astatine (At) are all metalloids

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The iodine "clock reaction" involves the following sequence of reactions occurring in a reaction mixture in a single beaker. 1.

Mars2501 [29]

C: 0.012 mol.

<h3>Explanation</h3>

Start with 0.0020 moles of iodate ions ${\text{IO}_{3}}^{-}$ .

How many moles of iodine $\text{I}_2$ will be produced?

${\text{IO}_{3}}^{-}$ converts to $\text{I}_2$ in the first reaction. The coefficient in front of $\text{I}_2$ is three times the coefficient in front of ${\text{IO}_{3}}^{-}$ . In other words, each mole of ${\text{IO}_{3}}^{-}$ will produce three moles of $\text{I}_2$ . 0.0020 moles of ${\text{IO}_{3}}^{-}$ will convert to 0.0060 moles of $\text{I}_2$ .

How many moles of thiosulfate ions ${\text{S}_2\text{O}_3}^{2-}$ are required?

$\text{I}_2$ reacts with ${\text{S}_2\text{O}_3}^{2-}$ in the second reaction. The coefficient in front of $\text{I}_2$ is twice the coefficient in front of ${\text{S}_2\text{O}_3}^{2-}$ . How many moles of ${\text{S}_2\text{O}_3}^{2-}$ does each mole of $\text{I}_2$ consume? Two. 0.0060 moles of $\text{I}_2$ will be produced. As a result, $2 \times 0.0060 = 0.0120$ moles of ${\text{S}_2\text{O}_3}^{2-}$ will be needed.

6 0

2 years ago

Calculate the molecular weight of a substance. In which the solution of this substance in the water has a concentration of 7 per

Eduardwww [97]

Answer : The molecular weight of a substance is 157.3 g/mol

Explanation :

As we are given that 7 % by weight that means 7 grams of solute present in 100 grams of solution.

Mass of solute = 7 g

Mass of solution = 100 g

Mass of solvent = 100 - 7 = 93 g

Formula used :

$\Delta T_f=i\times K_f\times m\\\\T_f^o-T_f=k_f\times\frac{\text{Mass of substance(solute)}\times 1000}{\text{Molar mass of substance(solute)}\times \text{Mass of water(solvent)}}$

where,

$\Delta T_f$ = change in freezing point

$T_f^o$ = temperature of pure water = $0^oC$

$T_f$ = temperature of solution = $-0.89^oC$

$K_f$ = freezing point constant of water = $1.86^oC/m$

m = molality

Now put all the given values in this formula, we get

$(0-(-0.89))^oC=1.86^oC/m\times \frac{7g\times 1000}{\text{Molar mass of substance(solute)}\times 93g}$

$\text{Molar mass of substance(solute)}=157.3g/mol$

Therefore, the molecular weight of a substance is 157.3 g/mol

7 0

3 years ago

Write the Noble Gas Notation for Silicone

ozzi

Answer:

[Ne] 3s2 3p2

Explanation:

Neon (Ne) is the noble gas right before silicon (Si).

Then right after neon is the 3s subshell. It has two electrons and is full.

After 3s comes the 3p subshell, and silicon only has two electrons in the 3p subshell (you can just count the electrons in each subshell on your periodic table).

8 0

3 years ago

Please select the word from the list that best fits the definition

sammy [17]

Pretty sure it’s ,B. Microscope!

8 0

2 years ago

Krypton-79 has a half-life of 35 hours. how many half-lives have passed after 105 hours?

Nookie1986 [14]

The number of half -lives that has passed after 105 hours for krypton-79 that has half-life of 35 hours is calculated as below

if 1 half life = 35 hours

what about 105 hours = ? half-lives

= (1 half life x105 hours) /35 hours = 3 half-lives has passed after 105 hours

6 0

3 years ago