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3 years ago

What is the answer to this question?

Chemistry

2 answers:

rodikova [14]3 years ago

7 0

Answer:

Vertebrae

Explanation:

Vertebrae are the 33 individual bones that interlock with each other to form the spinal column. The vertebrae are numbered and divided into regions: cervical, thoracic, lumbar, sacrum, and coccyx (Fig. 2). Only the top 24 bones are moveable; the vertebrae of the sacrum and coccyx are fused.

mash [69]3 years ago

7 0

I believe the answer is vertebrae. There are 24 bones stacked up on each other that make up your backbone.

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Student added a strip of aluminium metal in aqueous copper(2)Sulfate but no reaction occured. Suggest a reason why.

kari74 [83]

Answer:

See Explanation

Explanation:

It is a common observation that a strip of aluminium metal in aqueous copper(II)Sulfate does not show any visible reaction. Aluminium is normally expected to displace copper in solution since it is higher than copper in the electrochemical series.

The reason for this is that aluminium forms an oxide film around its surface which prevents reaction with aqueous copper(II)Sulfate. This oxides film protects the aluminium surface such that it is now unable to react with the aqueous copper(II)Sulfate

7 0

2 years ago

Determine % yield if a student obtains 45 g of product in an experiment and the theoretical amount is determined to be 50 g

Katen [24]

Percentage yield=(actual yield/theoretical yield) x 100%
= (45/50) x 100%
= 90%

8 0

3 years ago

"An aqueous CaCl2 solution has a vapor pressure of 83.1mmHg at 50 ∘C. The vapor pressure of pure water at this temperature is 92

Lynna [10]

Answer : The the concentration of $CaCl_2$ in mass percent is, 41.18 %

Solution : Given,

Molar mass of water = 18 g/mole

Molar mass of $CaCl_2$ = 110.98 g/mole

First we have to calculate the mole fraction of solute.

According to the relative lowering of vapor pressure, the vapor pressure of a component at a given temperature is equal to the mole fraction of that component of the solution multiplied by the vapor pressure of that component in the pure state.

$\fac{p^o-p_s}{p^o}=X_B$

where,

$p^o$ = vapor pressure of the pure component (water) = 92.6 mmHg

$p_s$ = vapor pressure of the solution = 83.1 mmHg

$X_B$ = mole fraction of solute, $(CaCl_2)$

Now put all the given values in this formula, we get the mole fraction of solute.

$\fac{92.6-83.1}{92.6}=X_B$

$X_B=0.102$

Now we have to calculate the mole fraction of solvent (water).

As we know that,

$X_A+X_B=1\\\\X_A=1-X_B\\\\X_A=1-0.102\\\\X_A=0.898$

The number of moles of solute and solvent will be, 0.102 and 0.898 moles respectively.

Now we have to calculate the mass of solute, $(CaCl_2)$ and solvent, $(H_2O)$ .

$\text{Mass of }CaCl_2=\text{Moles of }CaCl_2\times \text{Molar mass of }CaCl_2$

$\text{Mass of }CaCl_2=(0.102mole)\times (110.98g/mole)=11.32g$

$\text{Mass of }H_2O=\text{Moles of }H_2O\times \text{Molar mass of }H_2O$

$\text{Mass of }H_2O=(0.898mole)\times (18g/mole)=16.164g$

Mass of solution = Mass of solute + Mass of solvent

Mass of solution = 11.32 + 16.164 = 27.484 g

Now we have to calculate the mass percent of $CaCl_2$

$Mass\%=\frac{\text{Mass of}CaCl_2}{\text{Mass of solution}}\times 100=\frac{11.32g}{27.484g}\times 100=41.18\%$

Therefore, the the concentration of $CaCl_2$ in mass percent is, 41.18 %

4 0

2 years ago

Give the molecular geometry and number of electron groups for sf4. give the molecular geometry and number of electron groups for

Andrei [34K]

Answer:

5 electron groups, see saw

Explanation:

During the formation of SF4, the sulfur atom usually bonds with each of four fluorine atoms where 8 of valence electrons are used. The four fluorine atoms have 3 lone pairs of electrons in its octet which will further utilize 24 valence electrons. In addition, two electrons are present as a lone pair on the sulfur atom. We can determine sulfur’s hybridization state by counting of the number of regions of electron density on sulphur (the central atom in the molecule). When bonding takes place there is a formation of 4 single bonds to sulfur and it has 1 lone pair. Looking at this, we can say that the number of regions of electron density is 5. The hybridization state is sp3d.

SF4 molecular geometry is seesaw with one pair of valence electrons. The molecule is polar. The equatorial fluorine atoms have 102° bond angles instead of the actual 120° angle. The axial fluorine atom angle is 173° instead of the actual 180° bond angle.

3 0

3 years ago

The superheated water vapor is at 15 MPa and 350°C. The gas constant, the critical pressure, and the critical temperature of wat

Vesnalui [34]

Answer:

0.01917 m^3/kg.

Explanation:

Given:

P = 15 MPa

= 1.5 × 10^4 kPa

T = 350 °C

= 350 + 273

= 623 K

Molar mass of water, m = (2 × 1) + 16

= 18 g/mol

= 0.018 kg/mol

R = 0.4615 kPa·m3/kg·K

Using ideal gas equation,

P × V = n × R × T

But n = mass/molar mass

V = (R × T)/P

V/M = (R × T)/P × m

= (0.4615 × 623)/1.5 × 10^4

= 0.01917 m^3/kg.

4 0

3 years ago

What is the answer to this question?​

What is the answer to this question?