What is an electrolyte?

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 mothball, composed of naphthalene (C10H8), has a mass of 1.52g. How many naphthalene molecules does it contain?

Anna35 [415]

The molar mass of naphthalene is calculated as follows,
10 x (12.01 g/ mol) + 8 x (1.01 g/mol) = 128.12 g/mol
Divide the given mass by the molar mass to determine the number of moles of naphthalene present in the ball.
n = 1.52 g / 128.12 g/mol = 0.01186 mole
Multiply the number of moles to number of moles per mole.
(0.01186 mol) x (6.022 x10^23 molecules / mole) = 7.14 x 10^21 molecules

8 0

3 years ago

Enter your answer in the provided box. From the data below, calculate the total heat (in J) needed to convert 0.304 mol of gaseo

diamong [38]

Answer:

-35,281.5 J

Explanation:

To convert the gaseous ethanol to liquid ethanol, three steps will occur. First, it will lose heat and the temperature will decrease until its boiling point, so from 300.0°C to 78.5°C. Thus, more heat will be lost, but now, with the temperature constant, so the gas will be converted to liquid. And then, the liquid will lose heat to decrease the temperature from 78.5°C to 25.0°C.

The total heat loss is the sum of the heats of each step. Because the heat is being removed from the system, it's negative. The first and last step occurs with a change in temperature, and so the heat is calculated by:

Q = m*c*ΔT

Where m is the mass, c is the specific heat of the gas (first step) or liquid (last step), and ΔT the temperature variation (final - initial). The mass of ethanol is the molar mass 46.07 g/mol multiplied by the number of moles, so:

m = 46.07 * 0.304 = 14.00 g

The second step occurs without a change in temperature, and the heat is then:

Q = -n*ΔH°vap

Where n is the number of moles, ΔH°vap is the heat of vaporization, and the minus signal indicates that the heat is being lost. Then, the heat of each step is:

Q1 = 14.00*1.43*(78.5 - 300,0) = -4434.43 J

Q2 = -0.304*40.5 = -12.312 kJ = -12312 J

Q3 = 14.00*2.45*(25.0 - 78.5) = -1835.05 J

Q = Q1 + Q2 + Q3

Q = -35,281.5 J

5 0

3 years ago

What types of evidence do scientists use to determine evolutionary relationships among groups

lions [1.4K]

There are several things that can help scientists evaluate which category something belongs to. The similarity in features is one of them. If two skulls looked alike, they were probably species of the same evolutionary category. For example say humans and monkeys rather than humans and dogs.
Similarly fossils have helped scientists categorise species. Study of the chromosomes (in cases with available chromosomes) can help scientists figure out a lot about the subjects and categorise them.

5 0

3 years ago

Each carbon atom of benzene is involved in two ________

coldgirl [10]

Answer:

Benzene is a combination of carbon and hydrogen atoms. The hybridization is sp2 type. During the hybridization of benzene, each carbon atom forms different bonds with two other similar carbon atoms instead of just one.

hope it helps!

please mark as the brainliest!

7 0

3 years ago