Which of the following would most likely happen if water did not form hydrogen bonds?

5. How can you tell the difference between CuS and Cu2S

Oxana [17]

Prominent copper sulfide minerals include Cu2S (chalcocite) and CuS (covellite).

8 0

3 years ago

Glycine, C2H5O2N, is important for biological energy. The combustion reaction of glycine is described by the following thermoche

vredina [299]

Answer:

-537.25 kJ/mol is the standard enthalpy of formation of solid glycine.

Explanation:

$4C_2H_5O_2N(s) + 9O_2(g)\rightarrow 8CO_2(g) + 10H_2O(l) + 2N_2(g) ,\Delta H^{rxn} =-3896 kJ/mol$

Standard enthalpy of formation of oxygen gas= $\Delta H_{f,O_2}=0$

Standard enthalpy of formation of carbon dioxide= $\Delta H_{f,CO_2}=-393.5 kJ/mol$

Standard enthalpy of formation of water = $\Delta H_{f,H_2O}=-285.8 kJ/mol$

Standard enthalpy of formation of nitrogen gas= $\Delta H_{f,N_2}=0$

Standard enthalpy of formation of glycine = $\Delta H_{f,gly}=?$

Enthalpy of the reaction = $H_{rxn}=-3896 kJ/mol$

$H_{rxn} =$

= $8\times \Delta H_{f,CO_2} +10\times \Delta H_{f,H_2O}+2\times \Delta H_{f,N_2} - (4\times \Delta H_{f,gly}+9\times \Delta H_{f,O_2})$

$-3896 kJ/mol=8\times (-393.5 kJ/mol)+ 10\times (-285.8 kJ/mol)+0 - (4\times \Delta H_{f,gly} +0)$

On rearranging :

$4\times \Delta H_{f,gly}=8\times (-393.5 kJ/mol)+ 10\times (-285.8 kJ/mol)+ 3896 kJ/mol$

$\Delta H_{f,gly}=\frac{-2149 kJ/mol}{4}=-537.25 kJ/mol$

-537.25 kJ/mol is the standard enthalpy of formation of solid glycine.

6 0

3 years ago

How can the shape of a molecule determine its polarity?

Makovka662 [10]

Answer:

Think of each polar bond in a molecule as a little arrow pointing from positive to negative. This tells us that the bond dipole is a vector quantity. Like any other vector quantity, the direction is a vital aspect of its description. So, the geometry of the molecule determines the direction that the bond dipole vectors point. The polarity of the molecule results from adding up all these individual bond dipoles.

Explanation:

Hope this helped Mark BRAINLIEST!!!

6 0

3 years ago

Which sphere forms Earth's outermost layer?

svetoff [14.1K]

Answer: I believe the answer is A.

Explanation: Well, the lithosphere is rocks and earth, the hydrosphere makes up all the water on Earth, the biosphere is us, (living things,) and the atmosphere is the air that surrounds us and our planet. So if you go in order, it's basically lithosphere, hydrosphere, biosphere, and then atmosphere.

7 0

3 years ago

A student performed a serial dilution on a stock solution of 1.33 M NaOH. A 2.0 mL aliquot of the stock NaOH (ms) was added to 1

guapka [62]

Answer:

$\boxed{1.33 \times 10^{-5}\, \text{mol/L}}}$

Explanation:

Data:

c₀ = 1.33 mol·L⁻¹

Dilutions = 2 mL stock + 18 mL water

n = five dilutions

Calculations:

The general formula is for calculating a single dilution ratio (DR) is

$DR = \dfrac{V_{i}}{V_{f}}$

For your dilutions,

$V_{i} = \text{2 mL}\\V_{f} = \text{20 mL}\\DR = \dfrac{ \text{2 mL}}{\text{20 mL}} = \dfrac{1}{10}$

(Note: This is the same as a dilution factor of 10:1)

The general formula for the concentration cₙ after n identical serial dilutions is

$c_{n} = c_{0}(\text{DR})^{n}$

So, after five dilutions

$c_{5} =1.33 \left (\dfrac{1}{10} \right )^{5}=1.33\left ( \dfrac{1}{10^{5}} \right ) = \mathbf{1.33 \times 10^{-5}}\textbf{ mol/L}\\\\\text{The final concentration is $\boxed{\mathbf{1.33 \times 10^{-5}\, mol/L}}$}$

5 0

3 years ago