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3 years ago

Gold atoms can be identified based on the number of which subatomic particles?

Chemistry

2 answers:

sp2606 [1]3 years ago

7 0

Answer: A

Explanation:

A Gold (Au) atom has 79 protons and 79 electrons. A typical gold atom has 118 neutrons, though there are 18 other radioisotopes discovered so far. 79 is its charge (atomic number), which is both its proton number and electron number

dalvyx [7]3 years ago

6 0

D. Protons, if you change the number of protons you change the element. You cannot change nuclei. You can have the same element with different numbers of neutrons (isotopes) and different numbers of electrons (ions). So protons will allow you to identify the element.

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An acid with the general formula RCOOH is used to make a 0.10 M solution in water. The pH of this acid solution is measured as 3

Sati [7]

Answer:

0.159 \%

Explanation:

The acid will dissociate according to the reaction shown below:-

$RCOOH + H_2O\rightleftharpoons RCOO^- + H_3O^+$

Given that, pH=3.8

The concentration of can be determined from the expression fo pH as:-

pH = - log $[H^+]$

3.8 = - log $[H^+]$

$[H^+]$ = $1.59\times 10^{-4}\ M$

The initial concentration of RCOOH was 0.10 M, then the percent dissociation was- calculated as shown below:-

$\% \ dissociation=\frac{1.59\times 10^{-4}}{0.10}\times 100=0.159\ \%$

3 0

2 years ago

The bright-line spectrum of an element in the gaseous phase is produced as

sesenic [268]

Electrons move from higher energy states to lower energy states Hope this helped

3 0

3 years ago

Co(g) effuses at a rate that is ______ times that of cl2(g) under the same conditions.

il63 [147K]

Answer is: the ratio of the effusion rate is 1.59 : 1.

1) rate of effusion of carbon monoxide gas = 1/√M(CO).

rate of effusion of carbon monoxide gas = 1/√28.

rate of effusion of carbon monoxide gas = 0.189.

2) rate of effusion of chlorine = 1/√M(Cl₂).

rate of effusion of chlorine = 1/√70.9.

rate of effusion of chlorine = 0.119.

rate of effusion of carbon monoxide : rate of effusion of chlorine =

= 0.189 : 0.119 / ÷0.119.

rate of effusion of carbon monoxide : rate of effusion of chlorine = 1.59 : 1.

4 0

3 years ago

Use the standard reaction enthalpies given below to determine ΔH°rxn for the following reaction:P4(g) + 10 Cl2(g) → 4PCl5(s) ΔH°

miskamm [114]

<u>Answer:</u> The $\Delta H^o_{rxn}$ for the reaction is -1835 kJ.

<u>Explanation:</u>

Hess’s law of constant heat summation states that the amount of heat absorbed or evolved in a given chemical equation remains the same whether the process occurs in one step or several steps.

According to this law, the chemical equation is treated as ordinary algebraic expressions and can be added or subtracted to yield the required equation. This means that the enthalpy change of the overall reaction is equal to the sum of the enthalpy changes of the intermediate reactions.

The given chemical reaction follows:

$P_4(g)+10Cl_2(g)\rightarrow 4PCl_5(s)$ $\Delta H^o_{rxn}=?$

The intermediate balanced chemical reaction are:

(1) $PCl_5(s)\rightarrow PCl_3(g)+Cl_2(g)$ $\Delta H_1=157kJ$ ( × 4)

(2) $P_4(g)+6Cl_2(g)\rightarrow 4PCl_3(g)$ $\Delta H_2=-1207kJ$

The expression for enthalpy of the reaction follows:

$\Delta H^o_{rxn}=[4\times (-\Delta H_1)]+[1\times \Delta H_2]$

Putting values in above equation, we get:

$\Delta H^o_{rxn}=[(4\times (-157))+(1\times (-1207))=-1835kJ$

Hence, the $\Delta H^o_{rxn}$ for the reaction is -1835 kJ.

6 0

3 years ago

How many grams of iron are needed to combine with 24.9 g of 0 to make Fe203?

Pavlova-9 [17]

Answer:

Explanation:

Here's where all that equation balancing is going to come into use. Since the main object of the question is not the equation, I'm just going to balance it and use it.

4Fe + 3O2 ====> 2Fe2O3

Step One

Find the number of mols of O2 in 24.9 grams of O2

1 mol O2 = 2*16 = 32 grams

x mol O2 = 24.9 grams Cross multiply

32x = 24.9 * 1 Divide by 32

x = 24.9/32

x = 0.778 moles of O2

Step Two

Type the findings under the balanced equations parts. Solve for the number of moles of Fe

4Fe + 3O2 ====> 2Fe2O3

x 0.778

Step Three

Set up the proportion

4/x = 3/0.778 Cross multiply

Step Four

Solve the proportion moles of Fe

4*0.778 = 3x

3.112 = 3x Divide by 3

3.112/3 = 3x/3

x = 1.037 moles of Fe

Step Five

Find the mass of Fe

1 mol Fe = 56 grams

1.037 mol Fe = x Cross Multiply

x = 56*1.037

x = 58.1 grams

4 0

3 years ago