Which piece of evidence is an indication that a chemical reaction has occurred?

How many moles are in 5.4x1024 molecules of C4H2F7I, heptafluoro-1-iodobutane? Group of answer choices

jasenka [17]

Given :

Number of molecules of $C_4H_2F_7I$ .

To Find :

How many moles are in given number of molecules.

Solution :

We know, in 1 moles of any element/compound contains $6.022\times 10^{23}$ at atoms/molecules.

So, number of moles in $5.4\times 10^{24}$ molecules are :

$n = \dfrac{5.4\times 10^{24}}{6.022\times 10^{23}}\\\\n = 8.97 \ moles$

Therefore, number of moles are 8.97 .

4 0

3 years ago

Calculate the amount of heat required to completely sublime 55.0 g of solid dry ice CO2 at its sublimation temperature. The heat

aliina [53]

Answer:

40.4 kJ

Explanation:

Step 1: Given data

Mass of CO₂ (m): 55.0 g

Heat of sublimation of CO₂ (ΔH°sub): 32.3 kJ/mol

Step 2: Calculate the moles corresponding to 55.0 g of CO₂

The molar mass of CO₂ is 44.01 g/mol.

n = 55.0 g × 1 mol/44.01 g = 1.25 mol

Step 3: Calculate the heat (Q) required to sublimate 1.25 moles of CO₂

We will use the following expression.

Q = n × ΔH°sub

Q = 1.25 mol × 32.3 kJ/mol = 40.4 kJ

7 0

3 years ago

What occurs when a magnesium atom becomes a magnesium ion?

IgorLugansk [536]

The atom then has more protons than electrons and so it will be positively charged, a positive ion. Example: A magnesium atom may lose two electrons and become a Mg2+ ion. Non-metal atoms may gain electrons and become negatively charged. ... (It loses two electrons.)

6 0

3 years ago

Individual solute particles are broken apart from the solid by these particles. * a Solution b Insoluble c Solvent d Compounds

Maru [420]

Answer:

Individual solute particles are broken apart from the solid by the;

c. Solvent

Explanation:

A solution is the homogeneous mixture that is made up of two or more substances formed by dissolving a substance which can be a solid, liquid or gas in another substance known as the solvent which normally the larger part of the fraction of the solution than the solute and can also be a solid, liquid or a gas

In a solution the solvent particles serves to brake of and disperser parts of a solid solute to form a more or less homogeneous mixture

Therefore, the solute particles are broken by the solvent particles in a solution

7 0

3 years ago

Match the following reactions with the reaction type. You may use each type more than once.

vaieri [72.5K]

Answer:

1) Decomposition

2)Double-replacement reaction

3)synthesis

4)Double-replacement reaction

5)single-replacement reaction

6)Double-replacement reaction

Explanation:

Step 1: Data given

Synthesis: This is a reaction where two or more reactants will combine to form a new, single product. This is occurs when two or more reactants combine to form a single product. This can be shown with the following equation.

A + B → C

A and B are the reactants to form a new product C

Decomposition: This is a reaction where 1 (more complex) compound will be broken down into 2 or more (more simple) products.

This can be shown by the following equation:

AB → A + B

A single replacement: This is a reaction where one element wil be replaced by another element in the same compound. This can be shown by the following equation:

A + BC → B + AC

Here is the elemnt B in the compound BC, replaced by the element A, to form a new compound AC

A double-replacement: This is a reaction where the positive and negative ions of two ionic compounds will be exchanged and 2 new compounds willbe formed. This can be shown by the following equation:

AB+CD→AD+BC

A combustion reaction requires oxygen gas (O2) to produce the products CO2 and H2O

Step 2:

1) 2HgO(s) → 2Hg(l) + O2(g)

⇒ Decomposition

2) KCl(aq) + AgNO3(aq) → AgCl(s) + KNO3(aq)

⇒ Double-replacement reaction

3) 2Na(s) + H2(g) → 2NaH(s)

⇒ synthesis

4) Mg(OH)2(aq) + 2HNO2(aq) → Mg(NO2)2(aq) + 2 H2O(l)

⇒ Double-replacement reaction

5) Ca(s) + 2AgNO3(aq) → Ca(NO3)2(aq) + Ag(s)

⇒ Single-replacement reaction

6) Al2O3(s) + H2SO4(aq) → Al2(SO4)3(aq) + H2O(l)

⇒ Double-replacement reaction

8 0

3 years ago