Help! Quicklyyyy! Easy science thing.

Explain how you would decide which represents a greater mass: 3.25 x 1022 atoms of Ca or 2.45 grams of Mg?

elena55 [62]

Answer:

You need to convert the number of atoms of Ca into mass in grams, using Avogadro's number and the atomic mass of Ca.

Explanation:

The amount of matter is measured in grams. Thus, you need to convert the number of atoms of Ca (calcium) into mass to compare with 2.45 grams of Mg.

To convert the atoms of calcium into mass, you divide by Avogadro's number, to obtain the number of moles of atoms, and then divide by the atomic mass of calcium.

1. Number of moles, n

$n=\dfrac{\text{number of atoms}}{\text{Avogadro's number}}\\ \\ \\ n=\dfrac{3.25\times 10^{22}}{6.022\times 10^{23}}=0.053969mol$

2. Mass

mass = number of moles × atomic mass

mass = 0.053969mol × 40.078g/mol = 2.16g

Then, 2.45 g of Mg represent a greaer mass than the 3.25 × 10²² atoms of Ca.

4 0

3 years ago

A bomb calorimetric experiment was run to determine the enthalpy of combustion of ethanol. The reaction is The bomb had a heat c

gulaghasi [49]

Answer:

The enthalpy of combustion of ethanol in kJ/mol is -1419.58 kJ/mol.

Explanation:

The heat absorbed by the bomb and water is equal to the product of the heat capacity and the temperature change. Working with this equation, and assuming no heat is lost to the surroundings, we write :

qcal= Ccal × ΔT= 490 J/K × 276.7 K= 135,583 J = 135.58 kJ

Note we expressed the temperature change in K, because the heat capacity is written in K.

Now that we have the heat of combustion, we need to calculate the molar heat.

Because qsystem = qrxn + qcal and qrxn = -qcal, the heat change of the reaction is -135.58 kJ.

This is the heat released by the combustion of 4.40 g of ethanol ; therefore, we can write the conversion factor as 135.58 kJ/ 4.40 g.

The molar mass of ethanol is 46.07 g, so the heat of combustion of 1 mole of ethanol is :

molar heat of combustion= -135.58 kJ/4.40 g x 46.07 g/ 1 mol= -1419.58 kJ/mol

Therefore, the enthalpy of combustion of ethanol in kJ/mol is -1419.58 kJ/mol.

3 0

3 years ago

Dinitrogen pentoxide gas is formed by the reaction of nitrogen trioxide gas and nitrogen dioxide gas balanced equation

leonid [27]

Answer:

Balanced chemical equation:

NO₂ + NO₃ → N₂O₅

Explanation:

Chemical equation:

NO₂ + NO₃ → N₂O₅

Balanced chemical equation:

NO₂ + NO₃ → N₂O₅

Nitrogen trioxide gas combine with nitrogen dioxide gas and form nitrogen pentoxide.

This is the simple synthesis reaction in which two substance combine to form a new substance.

Synthesis reaction:

It is the reaction in which two or more simple substance react to give one or more complex product.

General chemical equation:

A + B → AB

A and B are reactants that combine to form AB product.

7 0

3 years ago

What is the molarity of a solution in which 7.1 g of sodium sulfate is dissolved in enough water to make 100. mL of solution?

Sidana [21]

Answer:

0.50 M

Explanation:

Given data

Mass of sodium sulfate (solute): 7.1 g

Volume of solution: 100 mL

Step 1: Calculate the moles of the solute

The molar mass of sodium sulfate is 142.04 g/mol. The moles corresponding to 7.1 grams of sodium sulfate are:

$7.1g \times \frac{1mol}{142.02g} = 0.050mol$

Step 2: Convert the volume of solution to liters

We will use the relation 1 L = 1000 mL.

$100mL \times \frac{1L}{1000mL} =0.100L$

Step 3: Calculate the molarity of the solution

$M = \frac{moles\ of\ solute }{liters\ of\ solution} = \frac{0.050mol}{0.100L} =0.50 M$

3 0

3 years ago

Read 2 more answers

Why don't noble gases bond?

Luba_88 [7]

Their outer shells are filled So much that they don't need to bond or react with any other atoms.

7 0

3 years ago