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3 years ago

What mass is in 5 moles of helium?

Chemistry

1 answer:

ArbitrLikvidat [17]3 years ago

3 0

Answer:

Mass = 20 g

Explanation:

Given data:

Number of moles of He = 5 mol

Mass of He = ?

Solution:

Formula:

Number of moles = mass/ molar mass

Molar mass = 4 g/mol

by putting values,

5 mol = Mass / 4 g/mol

Mass = 5 mol × 4 g/mol

Mass = 20 g

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Scientists have put forth many types of alternative energy, one of which is nuclear power. Some people believe that nuclear powe

Oksana_A [137]

Answer:

With the appropriate security measures nuclear power, as well as other energy sources, can be used safely.

Explanation:

Nuclear energy, as well as other energy sources, can be dangerous if we do not take the appropriate prevention and protection measures. Nuclear power has one of the lowest levels of fatalities per unit of energy generated, as well as low levels of air pollution-related deaths and allows the reduction of carbon dioxide emissions compared to other energy sources. Since its commercialization, in the 70s, the number of nuclear power accidents is very low compared to the number of accidents of other energy sources, having that coal mining is the most dangerous energy activity in history.

I think that without the correct security considerations, all the energy sources can be dangerous, but if we take security measures as using protection barriers, controlling the reactivity of nuclear power plant, making regularly quality and prevention test control, as well as other measures, we can have the benefits of the nuclear power without worrying too much for danger.

Therefore, with the appropriate security measures nuclear power, as well as other energy activities, can be used safely.

I hope it helps you!

8 0

4 years ago

Divide the numbers in around the answer to the correct number of significant figures.

Zina [86]

Answer:

$\large \boxed{19.0}$

Explanation:

In multiplication and division problems, the answer can have no more significant figures than the number with the fewest significant figures.

A calculator gives the result:

$\dfrac{163.8}{8.64} = \mathbf{18.95833333}$

163.8 has four significant figures.

8.64 has three significant figures.

You must round to three significant figures.

That is, you drop all the digits to the right of the 9 — the red line in Fig. 1 below. You are rounding to the nearest tenth.

To round a number to the nearest tenth, you look at the digit in the hundredths place (7). See Fig. 2.

If the digit to be dropped is greater than 5 or is 5 followed by at least one non-zero digit, you add 1 to the number in the tenths place (Fig. 3).

Here's how you do it.

The digit in the hundredths place is 5 followed by non-zero digits.
Add 1 to the digit in the tenths place (9).
⁹/₁₀ + ⅒ = ¹⁰/₁₀ = 1 + ⁰/₁₀ = 1.0

The tenths digit becomes 0 and the ones digit increases from 8 to 9.

$\text{The quotient of $\dfrac{163.8}{18.64}$ is $\large \boxed{\mathbf{19.0}}$}$

7 0

3 years ago

PtichkaEL [24]

Answer:

c) 35 fl oz

Explanation:

Hello,

In this case, to compute the recommended amount of calcium that the teenager must drink, one performs the following relationship:

$8.0-fl \ oz -->298mg\\x-->1,300mg$

Solving for $x$ , one gets:

$x=\frac{8.0-fl \ oz *1,300mg}{298mg} \\x=35-fl \ oz$

Best regards.

5 0

4 years ago

A particular 3.0 L solution contains 2.5 mmol (millimoles) of a substance. What is the concentration of this solution in number

bearhunter [10]

Answer: 0.83mol/m3

Explanation:

Number of mole = 2.5 mmol = 0.0025mol

Recall

1L = 0.001m3

Therefore 3L = 3x0.001 = 0.003m3

0.003m3 contains 0.0025mol

Therefore, 1m3 will contain = 0.0025/0.003 = 0.83mol

The concentration in mol/m3 is 0.83mol/m3

8 0

4 years ago

For the reaction A + B + C → D + E, the initial reaction rate was measured for various initial concentrations of reactants. The

Alik [6]

Answer : The rate for trial 5 will be $4.25\times 10^{-2}Ms^{-1}$

Explanation :

Rate law is defined as the expression which expresses the rate of the reaction in terms of molar concentration of the reactants with each term raised to the power their stoichiometric coefficient of that reactant in the balanced chemical equation.

For the given chemical equation:

$A+B+C\rightarrow D+E$