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3 years ago

Hecking skills activated

Chemistry

2 answers:

artcher [175]3 years ago

7 0

Answer:

yes 34

Explanation:

4/13 =0.307

diamong [38]3 years ago

6 0

Answer:

What a cute animal!

Explanation:

Well am sorry it isn't very familiar to me

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How many carbon atoms are present in 3.900 x 10-4 mol of carbon? Give your answer in scientific notation. x 10 (select) A

AnnyKZ [126]

<u>Answer:</u> The number of atoms of carbon present in given number of moles are $2.350\times 10^{20}$

<u>Explanation:</u>

We are given:

Number of moles of carbon = $3.900\times 10^{-4}mol$

According to mole concept:

1 mole of an element contains $6.022\times 10^{23}$ number of atoms.

So, $3.900\times 10^{-4}mol$ of carbon will contain = $3.900\times 10^{-4}\times 6.022\times 10^{23}=2.350\times 10^{20}$ number of atoms.

Hence, the number of atoms of carbon present in given number of moles are $2.350\times 10^{20}$

4 0

3 years ago

Which statement best describes the direction of heat flow by conduction between two samples of the same material?

tigry1 [53]

Answer: 2. Heat flows from faster molecules to slower molecules when they collide.

Explanation: Hope this helped! :)

6 0

4 years ago

Read 2 more answers

Calculate ΔHrxn for the following reaction: Fe₂O₃(s)+3CO(g)→2Fe(s)+3CO₂(g) Use the following reactions and given ΔH′s. 2Fe(s)+3/

ExtremeBDS [4]

Answer : The enthalpy change of reaction is -23.9 kJ

Explanation :

According to Hess’s law of constant heat summation, the heat absorbed or evolved in a given chemical equation is the same whether the process occurs in one step or several steps.

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

The given final reaction is,

$Fe_2O_3(s)+3CO(g)\rightarrow 2Fe(s)+3CO_2(g)$ $\Delta H=?$

The intermediate balanced chemical reaction will be,

(1) $2Fe(s)+\frac{3}{2}O_2(g)\rightarrow Fe_2O_3(s)$ $\Delta H^o_1=-824.2kJ$

(2) $CO(g)+\frac{1}{2}O_2(g)\rightarrow CO_2(g)$ $\Delta H^o_2=-282.7kJ$

First we will reverse the reaction 1 and multiply equation 2 by 3 then adding both the equation, we get :

(1) $Fe_2O_3(s)\rightarrow 2Fe(s)+\frac{3}{2}O_2(g)$ $\Delta H^o_1=+824.2kJ$

(2) $3CO(g)+\frac{3}{2}O_2(g)\rightarrow 3CO_2(g)$ $\Delta H^o_2=3\times (-282.7kJ)=-848.1kJ$

The expression for final enthalpy is,

$\Delta H=\Delta H^o_1+\Delta H^o_2$

$\Delta H=(+824.2kJ)+(-848.1kJ)$

$\Delta H=-23.9kJ$

Therefore, the enthalpy change of reaction is -23.9 kJ

7 0

3 years ago

Which best describes sodium chloride (NaCl)?

OverLord2011 [107]

Answer: NaCl is an ionic compound

Explanation: Sodium Chloride is formed from Na+ and Cl- ions.

It is soluble in water, it has crystalline structure, it has high melting point and

It is insulator as solid form. Water solution leads current.

4 0

3 years ago

If you start with 512 grams of aluminum and 1147 grams of copper chloride to make aluminum chloride and copper, what is the limi

Archy [21]

First you need to calculate the number of moles of aluminium and copper chloride.

number of moles = mass / molecular weight

moles of Al = 512 / 27 = 19 moles

moles of CuCl = 1147 / 99 = 11.6 moles

From the reaction you see that:

if 2 moles of Al will react with 3 moles of CuCl

then 19 moles of Al will react with X moles of CuCl

X = (19 × 3) / 2 = 28.5 moles of CuCl, way more that 11.6 moles of CuCl wich is the quantity you have. So the copper chloride is the limiting reagent.

6 0

3 years ago