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3 years ago

What is the formula for the percent of an element in a compound

1 answer:

4 0

The percent composition of a compound is calculated with the molecular formula: divide the mass of each element found in one mole of the compound by the total molar mass of the compound

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use the periodic table to select the element from the drop-down menu that has the correct relative electronegativity.

Bumek [7]

You need to list the elements but remember that fluorine has the highest electronegativity out of the entire periodic table

6 0

3 years ago

Read 2 more answers

Consider the intermediate chemical reactions. 2 equations. First: upper C a (s) plus upper C upper O subscript 2 (g) plus one ha

DochEvi [55]

<u>Answer:</u> When the enthalpy of this overall chemical equation is calculated, the enthalpy of the second intermediate equation is halved and has its sign changed.

<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 overall chemical reaction follows:

$CaO(s)+CO_2\rightarrow CaCO_3(s)$ $\Delta H^o_{rxn}=?$

The intermediate balanced chemical reaction are:

(1) $Ca(s)+CO_2(g)+\frac{1}{2}O_2(g)\rightarrow CaCO_3(s)$ $\Delta H_1=-812.8kJ$

(2) $2Ca(s)+O_2(g)\rightarrow 2CaO(s)$ $\Delta H_2=-1269kJ$

The expression for enthalpy of the reaction follows:

$\Delta H^o_{rxn}=[1\times (\Delta H_1)]+[\frac{1}{2}\times (-\Delta H_2)]$

Hence, when the enthalpy of this overall chemical equation is calculated, the enthalpy of the second intermediate equation is halved and has its sign changed.

3 0

3 years ago

Even though we are well into the course Dumbledore notices some of the students are still having trouble with significant figure

Sphinxa [80]

Answer:

B) 2

Explanation:

Significant figures : The figures in a number which express the value -the magnitude of a quantity to a specific degree of accuracy is known as significant digits.

The rule apply for the multiplication and division is :

The least number of significant figures in any number of the problem determines the number of significant figures in the answer.

The rule apply for the addition and subtraction is :

The least precise number present after the decimal point determines the number of significant figures in the answer.

(3.478-2.31) = 1.168 ≅ 1.17 (Rounded to least decimal digit)

(4.428-3.56) = 0.868 ≅ 0.87 (Rounded to least decimal digit)

So,

1.17 * 0.87 = 1.0 (Rounded to least significant)

Answer - two significant digits

5 0

3 years ago

Oxygen and hydrogen are both elements that are found as gases at room temperature. When oxygen combines with hydrogen, they prod

Tom [10]

Answer:

Explanation:

has properties that are different from the original substances.

5 0

3 years ago

Which substance can be broken down by a chemical change

ELEN [110]

Lots of substances. Rocks, metals, minerals, you name it.

5 0

3 years ago

Read 2 more answers