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2 years ago

What needs to occur in order for elements to form a compound?

Chemistry

2 answers:

gizmo_the_mogwai [7]2 years ago

7 0

When 2 or more elements combine chemically

SCORPION-xisa [38]2 years ago

5 0

Answer:

When two distinct elements are chemically combined.

Explanation:

Chemical bonds form between their atoms the result is called a chemical compound. Most elements on Earth bond with other elements to form chemical compounds, such as sodium (Na) and Chloride (Cl), which combine to form table salt (NaCl)

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A 4Kg rock is rolling 10m/s find it’s kinetic energy

Lubov Fominskaja [6]

KE=.5mv^2
M=mass
v=velocity
.5(4)(100)=200
That should be the answer.

5 0

3 years ago

N₂O(g) + 3 H₂(g) N₂H4(1) + H₂O(1) AH = -317 kJ/mol

docker41 [41]

Answer:

Explanation:

Recall that Δ<em>H</em> is the sum of the heats of formation of the products minus the heat of formation of the reactants multiplied by their respective coefficients. That is:

$\displaystyle \Delta H^\circ_{rxn} = \sum \Delta H^\circ_{f} \left(\text{Products}\right) - \sum \Delta H^\circ_{f} \left(\text{Reactants}\right)$

Therefore, from the chemical equation, we have that:

$\displaystyle \begin{aligned} (-317\text{ kJ/mol}) = \left[\Delta H^\circ_f \text{ N$_2$H$_4$} + \Delta H^\circ_f \text{ H$_2$O} \right] -\left[3 \Delta H^\circ_f \text{ H$_2$}+\Delta H^\circ_f \text{ N$_2$O}\right] \end{aligned}$

Remember that the heat of formation of pure elements (e.g. H₂) are zero. Substitute in known values and solve for hydrazine:

$\displaystyle \begin{aligned} (-317\text{ kJ/mol}) & = \left[ \Delta H^\circ _f \text{ N$_2$H$_4$} + (-285.8\text{ kJ/mol})\right] -\left[ 3(0) + (82.1\text{ kJ/mol})\right] \\ \\ \Delta H^\circ _f \text{ N$_2$H$_4$} & = (-317 + 285.8 + 82.1)\text{ kJ/mol} \\ \\ & = 50.9\text{ kJ/mol} \end{aligned}$

In conclusion, our answer is A.

5 0

2 years ago

Does adding 1 mol of NaCl to 1 kg of water lower the vapor pressure of water to the same extent, a lesser extent, or a greater e

igor_vitrenko [27]

Answer:

Adding 1 mol of NaCl to 1 kg of water lower the vapor pressure of water <em><u>to the same extent</u></em> by adding 1 mol of $C_06H_{12}O_6$ to 1 kg of water.

Explanation:

1) Moles of NaCl , $n_1=1 mol$

Mass of water = m= 1 kg = 1000 g

Moles of water = $n_2=\frac{1000 g}{18 g/mol}=55.55 mol$

Vapor pressure of the solution = $p$

Vapor pressure of the pure solvent that is water = $p_o=17.5 Torr$

Mole fraction of solute(NaCl)= $\chi_1=\frac{n_1}{n_1+n_2}$

$\frac{p_o-p}{p_o}=\frac{n_1}{n_1+n_2}$

$\frac{17.5 Torr-p}{17.5 Torr}=\frac{1 mol}{1 mol+55.55 mol}$

$p=17.19 Torr$

The vapor pressure for the NaCl solution at 17.19 Torr.

2) Moles of sucrose , $n_1=1mol$

Mass of water = m = 1 kg = 1000 g

Moles of water = $n_2=\frac{1000 g}{18 g/mol}=55.55 mol$

Vapor pressure of the solution = $p'$

Vapor pressure of the pure solvent that is water = $p_o=17.5 Torr$

Mole fraction of solute ( glucose)= $\chi_1=\frac{n_1}{n_1+n_2}$

$\frac{p_o-p}{p_o}=\frac{n_1}{n_1+n_2}$

$\frac{17.5 Torr-p}{17.5 Torr}=\frac{1 mol}{1 mol+55.55 mol}$

$p'=17.19 Torr$

The vapor pressure for the glucose solution at 17.19 Torr.

p = p' = 17.19 Torr

Adding 1 mol of NaCl to 1 kg of water lower the vapor pressure of water to the same extent by adding 1 mol of $C_06H_{12}O_6$ to 1 kg of water.

3 0

3 years ago

Enter the number of unique signals in the 1H NMR spectrum of ethanol. Assume that the hydroxy proton does NOT exchange with the

ss7ja [257]

Answer:

In the 1H NMR spectrum of ethanol three different signals are observed, this is due to the existence of 3 types of hydrogens with different chemical environment. Hydrogens A (3.57 ppm) are more screened than C (1.10 ppm) due to the presence of oxygen (electonegative atom that removes electron density). The chemical environment of hydrogen B (4.78 ppm), attached directly to oxygen, is also different by resonating at a frequency different from the previous ones.

$C1HC_{3} -C2HA_{2} -OHB$

The hydroxylic hydrogen produces a singlet, the pair of carbon hydrogens one give rise to a quadruplet and the three hydrogens of carbon two produce a triplet.

Explanation:

5 0

2 years ago

What state of matter is Polaris, the north star?

Anni [7]

The state of matter of Polaris, the north star is gas.

<h3>What are stars made of?</h3>

Stars are made up of a mixture of hot gases.

The mixture consists of helium and hydrogen. Hydrogen burns into helium to give starts a shining appearance when observed from a far distance.

Thus, the state of matter of all stars, including the north star, is gas.

More on stars can be found here: brainly.com/question/21521087

#SPJ1

8 0

1 year ago