Which of these elements is the most reactive? potassium calcium titanium scandium

The solid anhydrous solid CoCl2 is blue in color. Because it readily absorbs water from the air, it is used as a humidity indica

MrRissso [65]

Answer:

$CoCl_{2}.(H_{2}O)_{6}$ is formed and it has three unpaired electrons.

Explanation:

Blue $CoCl_{2}$ reacts with water to produce pink colored $CoCl_{2}.(H_{2}O)_{6}$ complex.

In this complex, $Co^{2+}$ ion forms an octahedral complex with six $H_{2}O$ ligands.

As $H_{2}O$ is a weak field ligand therefore $Co^{2+}$ ion remains in low spin state.

Hence electronic configuration of $Co^{2+}$ ion in this octahedral geometry is $t_{2g}^{5}e_{g}^{2}$ with total three unpaired electrons.

6 0

3 years ago

The flask contains 10.0 mL of HCl and a few drops of phenolphthalein indicator. The buret contains 0.160 M NaOH. It requires 18.

olchik [2.2K]

Answer:

Approximately $0.291\; \rm M$ (rounded to two significant figures.)

Explanation:

The unit of concentration $\rm M$ is the same as $\rm mol \cdot L^{-1}$ (moles per liter.) On the other hand, the volume of both the $\rm NaOH$ solution and the original $\rm HCl$ solution here are in milliliters. Convert these two volumes to liters:

$V(\mathrm{NaOH}) = 18.2\; \rm mL = 18.2 \times 10^{-3}\; \rm L = 0.0182\; \rm L$ .
$V(\text{$\mathrm{HCl}$, original}) = 10.0\; \rm mL = 10.0\times 10^{-3}\; \rm L = 0.0100\; \rm L$ .

Calculate the number of moles of $\rm NaOH$ in that $0.0182\; \rm L$ of $0.160\; \rm M$ solution:

$\begin{aligned} n(\mathrm{NaOH}) &= c(\mathrm{NaOH})\cdot V(\mathrm{NaOH})\\ &= 0.160\; \rm mol \cdot L^{-1} \times 0.0182\; \rm L \approx 0.00291\; \rm mol\end{aligned}$ .

$\rm HCl$ reacts with $\rm NaOH$ at a one-to-one ratio:

$\rm HCl\; (aq) + NaOH\; (aq) \to NaCl\; (aq) + H_2O\; (l)$ .

Coefficient ratio:

$\displaystyle \frac{n(\mathrm{HCl})}{n(\mathrm{NaOH})} = 1$ .

In other words, one mole of $\rm NaOH$ would neutralize exactly one mole of $\rm HCl$ . In this titration, $0.291\; \rm mol$ of $\rm NaOH\!$ was required. Therefore, the same amount of $\rm HC$ should be present in the original solution:

$\begin{aligned}&n(\text{$\mathrm{HCl}$, original})\\ &= n(\mathrm{NaOH})\cdot \frac{n(\mathrm{HCl})}{n(\mathrm{NaOH})} \\ &\approx 0.00291\; \rm mol \times 1 = 0.00291\; \rm mol\end{aligned}$ .

Calculate the concentration of the original $\rm HCl$ solution:

$\displaystyle c(\text{$\mathrm{HCl}$, original}) = \frac{n(\text{$\mathrm{HCl}$, original})}{V(\text{$\mathrm{HCl}$, original})} \approx \frac{0.00291\; \rm mol}{0.0100\; \rm L} \approx 0.291\; \rm M$ .

5 0

3 years ago

Lucille is finding it difficult to play soccer after school. Her doctor thinks that her cells might not be getting enough oxygen

Natali5045456 [20]

Answer:

They might not be bringing in enough oxygen from the air. It's hard to play soccer if you don't have enough oxygen in your cells. They might not be breaking down starch to make glucose.

Explanation:

6 0

2 years ago

Which class of biomolecule do the molecules in the table belong to?

kondaur [170]

The oythagorean theroem

8 0

2 years ago

GR 11 CHEM M3

galina1969 [7]

A: When burning Sulfur, Sulfur Dioxide is released. Having more Oxygen available provides more reactive potential for the burning Sulfur, making it burn much more fiercely. In water, the Sulfur Dioxide forms Sulfurous acid. Added: 12 years ago.

Explanation:

6 0

3 years ago