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3 years ago

CHEMISTRY HELP (50 PTS!!!!!!) picture attached

Chemistry

2 answers:

aleksandrvk [35]3 years ago

5 0

Answer:

<h2>B is the right answer </h2>

Explanation:

<h2>Hope this helps! If you have any other questions feel free to ask! If not then have a nice day and please consider making me Brainliest!! </h2>

vodomira [7]3 years ago

4 0

Answer:

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4. The nucleus of an atom is positively charged due to<br>A. electrons b. neutrons C. proton D. Ion

FinnZ [79.3K]

Answer:

Protons

Explanation:

Electrons have a negative charge which are found in shells around the nucleus. The nucleus consists of protons and neutron and the neutron has a neutral charge.

8 0

3 years ago

Read 2 more answers

Do any of the elements have similar properties?

Marysya12 [62]

Hello! Charchar here!

Answer:

I don't know what the elements are soo

The elements in the first column of the Periodic Table (other than hydrogen) are known as Group 1A metals, or alkali metals. When you compare the chemical properties of these elements (lithium, sodium, potassium, rubidium, cesium, and francium), what you'll notice is that they are all remarkably similar.

Explanation:

Hope this helped!

Have a nice day!

6 0

3 years ago

Given the following at 25C calculate delta Hf for HCN (g) at 25C. 2NH3 (g) +3O2 (g) + 2CH4 (g) ---> 2HCN (g) + 6H2O (g) delta

AysviL [449]

<u>Answer:</u> The $\Delta H_f$ for HCN (g) in the reaction is 135.1 kJ/mol.

<u>Explanation:</u>

Enthalpy change is defined as the difference in enthalpies of all the product and the reactants each multiplied with their respective number of moles. The equation used to calculate enthalpy change is of a reaction is:

$\Delta H_{rxn}=\sum [n\times \Delta H_f(product)]-\sum [n\times \Delta H_f(reactant)]$

For the given chemical reaction:

$2NH_3(g)+3O_2(g)+2CH_4(g)\rightarrow 2HCN(g)+6H_2O(g)$

The equation for the enthalpy change of the above reaction is:

$\Delta H_{rxn}=[(2\times \Delta H_f_{(HCN)})+(6\times \Delta H_f_{(H_2O)})]-[(2\times \Delta H_f_{(NH_3)})+(3\times \Delta H_f_{(O_2)})+(2\times \Delta H_f_{(CH_4)})]$

We are given:

$\Delta H_f_{(H_2O)}=-241.8kJ/mol\\\Delta H_f_{(NH_3)}=-80.3kJ/mol\\\Delta H_f_{(CH_4)}=-74.6kJ/mol\\\Delta H_f_{(O_2)}=0kJ/mol\\\Delta H_{rxn}=-870.8kJ$

Putting values in above equation, we get:

$-870.8=[(2\times \Delta H_f_{(HCN)})+(6\times (-241.8))]-[(2\times (-80.3))+(3\times (0))+(2\times (-74.6))]\\\\\Delta H_f_{(HCN)}=135.1kJ$

Hence, the $\Delta H_f$ for HCN (g) in the reaction is 135.1 kJ/mol.

8 0

3 years ago

3. Determine the moles of sodium, Na, containing 7.9x1024 atoms.

-BARSIC- [3]

Answer:

12.7mol Na.

Explanation:

Hello there!

In this case, according to the concept of mole, which stands for the amount of substance, we can recall the concept of Avogadro's number whereby we understand that one mole of any substance contains 6.022x10²³ particles, for the given atoms of sodium, we can calculate the moles as shown below:

$7.9x10^{23}atoms*\frac{1mol}{6.022x10^{23}atoms} \\\\$