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3 years ago

What type of change is boiling water? Why?

2 answers:

5 0

It'd be a physical change. This is because it's a change in the state of matter and not altering the chemical structure of water

ASHA 777 [7]3 years ago

4 0

When water heats to a boil, it is a physical change. The only thing that is changing is energy being added, it is still H2O.

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The atomic masses of 151eu and 153eu are 150.919860 and 152.921243 amu, respectively. The average atomic mass of europium is 151

vitfil [10]

Answer:- The natural abundance of $^1^5^1_E_u$ is 0.478 or 47.8% and $^1^5^3_E_u$ is 0.522 or 52.2% .

Solution:- Average atomic mass of an element is calculated from the atomic masses of it's isotopes and their abundances using the formula:

Average atomic mass = mass of first isotope(abundance) + mass of second isotope(abundance)

We have been given with atomic masses for $^1^5^1_E_u$ and $^1^5^3_E_u$ as 150.919860 and 152.921243 amu, respectively. Average atomic mass of Eu is 151.964 amu.

Sum of natural abundances of isotopes of an element is always 1. If we assume the abundance of $^1^5^1_E_u$ as n then the abundance of $^1^5^3_E_u$ would be 1-n .

Let's plug in the values in the formula:

$151.964=150.919860(n)+152.921243(1-n)$

151.964=150.919860n+152.921243-152.921243n

on keeping similar terms on same side:

$151.964-152.921243=150.919860n-152.921243n$

$-0.957243=-2.001383n$

negative sign is on both sides so it is canceled:

$0.957243=2.001383n$

$n=\frac{0.957243}{2.001383}$

$n=0.478$

The abundance of $^1^5^1_E_u$ is 0.478 which is 47.8%.

The abundance of $^1^5^3_E_u$ is = $1-0.478$

= 0.522 which is 52.2%

Hence, the natural abundance of $^1^5^1_E_u$ is 0.478 or 47.8% and $^1^5^3_E_u$ is 0.522 or 52.2% .

3 0

3 years ago

Consider the reaction. 2c(s,graphite) h2= c2h2(g) Based on the equation and the information in the table, what is the enthalpy o

xxTIMURxx [149]

<h3>The enthalpy of the reaction : C.226.73 kJ</h3><h3>Further explanation</h3>

Delta H reaction (ΔH) is the amount of heat change between the system and its environment

(ΔH) can be positive (endothermic = requires heat) or negative (exothermic = releasing heat)

The change in enthalpy in the formation of 1 mole of the elements is called enthalpy of formation

Delta H reaction (ΔH) is the difference between product enthalpy and reactant enthalpy (Hp-Hr)

Reaction :

2C + H2 -> C2H2

(ΔH) reaction = (ΔH) product - (ΔH) reactants

(ΔH) reaction = (ΔH) C2H2 - ((ΔH) C + (ΔH) H2)

for free element (ΔH) it has zero value, so (ΔH) C and (ΔH) H2 have zero value

From the available data: Hf (kJ / mol) C2 H2 (g)= 226.73

then

(ΔH) reaction = ΔH) C2H2 - ((ΔH) C + (ΔH) H2)

(ΔH) reaction = 226.73 - (0 + 0)

(ΔH) reaction = 226.73 (answer C)

<h3>Learn more</h3>

(ΔH) reaction

brainly.com/question/1889660

Keywords : (ΔH) reaction, C2H2

8 0

3 years ago

Read 2 more answers

Does anyone know the answer to this chemistry question?!? How much HCl is made when 2g of hydrogen reacts? H2+Cl2->2HCl

jonny [76]

<h3>Answer:</h3>

72.19 g HCl

<h3>Explanation:</h3>

We are given the reaction between hydrogen gas and chlorine gas as;

H₂(g) + Cl₂(g) → 2HCl(g)

Mass of hydrogen gas that reacts is 2 g

We are required to determine the amount of HCl produced

<h3>Step 1: Determine the number of moles of H₂ used </h3>

Moles = Mass ÷ molar mass

Molar mass of Hydrogen gas = 2.02 g/mol

Thus;

Moles = 2 g ÷ 2.02 g/mol

= 0.99 moles

<h3>Step 2: Moles of HCl produced </h3>

From the reaction equation, 1 mole of hydrogen gas reacts to produce 2 moles of HCl

Therefore, the mole ratio of H₂ : HCl = 1 : 2

Thus, moles of HCl = 0.99 moles × 2

= 1.98 moles

<h3>Step 3: Mass of HCl produced </h3>

To calculate mass we multiply the number of moles by molar mass

Molar mass of HCl =36.46 g/mol

Therefore;

Mass of HCl = 36.46 g/mol × 1.98 moles

= 72.19 g

Thus, the amount of HCl produced during the reaction is 72.19 g

3 0

3 years ago

1. Freon (CCl2F2) is commonly used in refrigerators and air conditioners as a coolant. How many grams of fluorine are there in t

Georgia [21]

Answer:

285g of fluorine

Explanation:

To solve this problem we need to find the mass of Freon in grams. Then, with its molar mass we can find moles of freon and, as 1 mole of Freon, CCl₂F₂, contains 2 moles of fluorine, we can find moles of fluorine and its mass:

<em>Mass Freon:</em>

<em>2.00lbs * (454g / 1lb) = </em>908g of Freon

<em>Moles freon -Molar mass: 120.91g/mol- and moles of fluorine:</em>

908g of Freon * (1mol / 120.91g) =

7.5 moles of freon * (2moles Fluorine / mole Freon): 15 moles of fluorine

<em>Mass fluorine -Atomic mass: 19g/mol-:</em>

15 moles F * (19g / mol) =

<h3>285g of fluorine</h3>

3 0

3 years ago

Reasons why water is a good cooling agent in machines

Fiesta28 [93]

Answer:

one reason is, Water is a very good liquid for cooling things down, for one thing there is plenty of it and it has also got a high specific heat capacity. This means that it can absorb a large amount of heat energy without getting too hot.

will not heat up or cool down very fast

Water has a high value of latent heat of vapourization so it has cooling properties.
hope this helps you. :)

Explanation:

4 0

2 years ago