What is always conserved in a chemical reaction? (3 points)

Element X has two isotopes. If 72.0% of the element has an isotope mass of 84.9 atomic mass units, and 28.0% of the element has

bija089 [108]

<h2>Answer:</h2>

Average atomic mass of an element is the sum of the masses of its isotopes each multiplied by its natural abundance

$\footnotesize \longrightarrow \: \rm Average \: atomic \: mass = \dfrac{ \sum\limits \: \% age \: of \: each \: isotope \times Atomic \: mass }{100} \\$

$\footnotesize \longrightarrow \: \rm Average \: atomic \: mass = \dfrac{ 72 \times84.9 + 28 \times 87 }{100} \\$

$\footnotesize \longrightarrow \: \rm Average \: atomic \: mass = \dfrac{ 6112.8 + 2436 }{100} \\$

$\footnotesize \longrightarrow \: \rm Average \: atomic \: mass = \dfrac{ 8548.8 }{100} \\$

$\footnotesize \longrightarrow \: \bf Average \: atomic \: mass = 85.488 \: amu \\$

8 0

2 years ago

What is the final temperature of the solution formed when 1.52 g of NaOH is added to 35.5 g of water at 20.1 °C in a calorimeter

Inessa [10]

Answer : The final temperature of the solution in the calorimeter is, $31.0^oC$

Explanation :

First we have to calculate the heat produced.

$\Delta H=\frac{q}{n}$

where,

$\Delta H$ = enthalpy change = -44.5 kJ/mol

q = heat released = ?

m = mass of $NaOH$ = 1.52 g

Molar mass of $NaOH$ = 40 g/mol

$\text{Moles of }NaOH=\frac{\text{Mass of }NaOH}{\text{Molar mass of }NaOH}=\frac{1.52g}{40g/mole}=0.038mole$

Now put all the given values in the above formula, we get:

$44.5kJ/mol=\frac{q}{0.038mol}$

$q=1.691kJ$

Now we have to calculate the final temperature of solution in the calorimeter.

$q=m\times c\times (T_2-T_1)$

where,

q = heat produced = 1.691 kJ = 1691 J

m = mass of solution = 1.52 + 35.5 = 37.02 g

c = specific heat capacity of water = $4.18J/g^oC$

$T_1$ = initial temperature = $20.1^oC$

$T_2$ = final temperature = ?

Now put all the given values in the above formula, we get:

$1691J=37.02g\times 4.18J/g^oC\times (T_2-20.1)$

$T_2=31.0^oC$

Thus, the final temperature of the solution in the calorimeter is, $31.0^oC$

4 0

3 years ago

What is the gulf stream.<br> a surface current<br> a deep current <br> a river <br> a climate event

guapka [62]

I think it’s a climate event

5 0

3 years ago

All of the elements on periodic table are found in nature true or false

Andreas93 [3]

Answer:

The answer would be true

Explanation:

Elements 1 through 92 (except for elements 43 and 61) occur naturally on Earth, although some are only present in extremely small quantities.

5 0

3 years ago

What type of chemical reaction

amm1812

Answer:

Oxidation or Exothermic reaction

Explanation:

Oxidation means gain of oxygen.

Exothermic means loss of heat to combine 2 elements

5 0

3 years ago