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3 years ago

Please answer asap!

1 answer:

4 0

1.) A compound is a thing that is composed of two or more (separate) elements.

2.) A compound cannot be separated easily, while its properties differ from where it originates from. It also is formed from chemical reactions.

3.) A pure substance, also known as chemical substance, is a material with constant composition and consistant properties.

4.) If a substance is not a pure substance, then it is an impure substance.

Hope this helped. :)

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Combustion of ethylene glycol leads to a change in internal energy (\DeltaU) of –1189 kJ at 298 K. What is the corresponding cha

ddd [48]

Answer:

-1190.24 kJ

Explanation:

The enthalpy change in a chemical reaction that produces or consumes gases is given by the expression:

ΔH = ΔU + Δngas RT

where Δn gas is the change of moles of gas, R is the gas constant,and T is temperature.

Now from the given balanced chemical reaction, the change in number of mol gas is equal to:

Δn gas = mole gas products - mole gas reactants = 2 - 5/2 = -1/2 mol

Sionce we know ΔU and the temperature (298 K), we are in position to calculate the change in enthalpy.

ΔH = -1189 x 10³ J + (-0.5 mol ) 8.314 J/Kmol x 298 K

ΔH = -1.190 x 10⁶ J = -1.190 x 10⁶ J x 1 kJ/1000 J = -1.190 x 10³ J

7 0

3 years ago

A 34.57 mL sample of an unknown phosphoric acid solution is titrated with a 0.127 M sodium hydroxide solution. The equivalence p

Bas_tet [7]

<u>Answer:</u> The concentration of unknown phosphoric acid solution is 0.034 M

<u>Explanation:</u>

To calculate the concentration of acid, we use the equation given by neutralization reaction:

$n_1M_1V_1=n_2M_2V_2$

where,

$n_1,M_1\text{ and }V_1$ are the n-factor, molarity and volume of acid which is $H_3PO_4$

$n_2,M_2\text{ and }V_2$ are the n-factor, molarity and volume of base which is NaOH.

We are given:

$n_1=3\\M_1=?M\\V_1=34.57mL\\n_2=1\\M_2=0.127M\\V_2=28.2mL$

Putting values in above equation, we get:

$3\times M_1\times 34.57=1\times 0.127\times 28.2\\\\M_1=\frac{1\times 0.127\times 28.2}{3\times 34.57}=0.034M$

Hence, the concentration of unknown phosphoric acid solution is 0.034 M

7 0

3 years ago

When a hydrochloric acid solution is combined with a potassium hydroxide solution, an acid-base reaction occur?

Mariulka [41]

when hydrochloric acid is added to a potassium hydroxide solution, the acid and base would react to form salt(potassium chloride) and water

Chemical Formula:

HCl(aq) +KOH(aq) ---> KCl (aq) + H20 (l)

3 0

3 years ago

Read 2 more answers

Which root word of the binary ionic compound ends with -ide

kondor19780726 [428]

Answer: C. The non metal

Explanation:-

For formation of a neutral ionic compound, the charges on cation and anion must be balanced. The cation is formed by loss of electrons by metals and anions are formed by gain of electrons by non metals.

The nomenclature of ionic compounds is given by:

1. Positive ion or metal is written first.

2. The negative ion or non metal is written next and a suffix is added at the end of the negative ion. The suffix written is '-ide'.

For example: $CsBr$ , cesium is metal having an oxidation state of +1 called as $Cs^{+}$ cation and bromine $Br^{-}$ is an anion with oxidation state of -1. Thus they combine and their oxidation states are exchanged and written in simplest whole number ratios to give neutral $CsBr$ called as cesium bromide.