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3 years ago

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Chemistry

2 answers:

jekas [21]3 years ago

8 0

Answer:

The correct answer is; 'The carbon sample would have three times the mass of the helium sample'.

Explanation:

Number of moles of carbon = 3.0 moles

Mass of 3 moles of carbon ,m= $3 moles\times 12 g/mol = 36 g$

Number of moles of helium = 3.0 moles

Mass of 3 moles of helium,m' = $3 moles\times 4 g/mol = 12 g$

Grams of carbon do we have more than grams of helium:

Mass of carbon > Mass of helium

$\frac{m}{m'}=\frac{36 g}{12 g}=3$

m = 3m'

The carbon sample would have three times the mass of the helium sample

bija089 [108]3 years ago

6 0

Protons + and electrons - must be equal

3 moles of C has a mass of 36, 3 moles of He is 12

so the answer is :
The carbon sample would have three times the mass of the helium sample

hope this helps

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I need help on both a and b of question 1

marishachu [46]

Answer:

(a) -0.00017 M/s;

(b) 0.00034 M/s

Explanation:

(a) Rate of a reaction is defined as change in molarity in a unit time, that is:

$r = \frac{\Delta c}{\Delta t}$

Given the following reaction:

$2 N_2O_5 (g)\rightleftharpoons 4 NO_2 (g) + O_2 (g)$

We may write the rate expression in terms of reactants firstly. Since reactants are decreasing in molarity, we're adding a negative sign. Similarly, if we wish to look at the overall reaction rate, we need to divide by stoichiometric coefficients:

$r = -\frac{\Delta [N_2O_5]}{2 \Delta t}$

Reaction rate is also equal to the rate of formation of products divided by their coefficients:

$r = \frac{\Delta [NO_2]}{4 \Delta t} = \frac{\Delta [O_2]}{\Delta t}$

Let's find the rate of disappearance of the reactant firstly. This would be found dividing the change in molarity by the change in time:

$r_{N_2O_5} = \frac{0.066 M - 0.100 M}{200.00 s - 0.00 s} = -0.00017 M/s$

(b) Using the relationship derived previously, we know that:

$-\frac{\Delta [N_2O_5]}{2 \Delta t} = \frac{\Delta [NO_2]}{4 \Delta t}$

Rate of appearance of nitrogen dioxide is given by:

$r_{NO_2} = \frac{\Delta [NO_2]}{\Delta t}$

Which is obtained from the equation:

$-\frac{\Delta [N_2O_5]}{2 \Delta t} = \frac{\Delta [NO_2]}{4 \Delta t}$

If we multiply both sides by 4, that is:

$-\frac{4 \Delta [N_2O_5]}{2 \Delta t} = \frac{\Delta [NO_2]}{\Delta t}$

This yields:

[tex]r_{NO_2} = \frac{\Delta [NO_2]}{\Delta t} = -2\frac{\Delta [N_2O_5]}{ \Delta t} = -2\cdot (-0.00017 M/s) = 0.00034 M/s[tex]

5 0

3 years ago

Suppose a compound is involved in three different reactions denoted R1, R2, and R3. Tripling the concentration of this reactant

pickupchik [31]

Answer:

The order of reaction is as follows, R1 = 1; R2 = 2; R3 = 0

Explanation:

The rate of a chemical reaction is the number of moles of reactants consumed per unit time or the number of moles of products formed per unit. the rate of a chemical reaction is affected by the concentration of reactants

The relationship between the rate of a chemical reaction and the concentration of its reactants is given by the rate law or equation.

Generally, the rate equation is given as;

Rate = k[A]ᵃ[B]ᵇ..., where k = rate constant which is independent of concentration of the reactants, [A] = concentration of reactant A, a = order of reaction A, [B] = concentration of reaction B, b = order of reaction B.

For the given reactions R1, R2 and R3

For R1; rate = 3, Concentration = 3[A]

3 = k[A]3ˣ

3¹ = k[A]3ˣ

Since rate is proportional to concentration, therefore, the order of reaction, x = 1

For R2; rate = 9, Concentration = 3[A]

9 = k[A]3ˣ

3² = k[A]3ˣ

Since rate is proportional to concentration, therefore, the order of reaction, x = 2

For R1; rate = 1, Concentration = 3[A]

1 = k[A]3ˣ

3⁰ = k[A]3ˣ

Since rate is proportional to concentration, therefore, the order of reaction, x = 0

Therefore, the order of reaction is as follows, R1 = 1; R2 = 2; R3 = 0

6 0

3 years ago

Explain in terms of atomic structure why the atomic radius of K is larger than that of Na

Lina20 [59]

Answer:

Potassium (K) has a larger average atomic radius (220 pm) than sodium (Na) does (180 pm). The potassium atom has an extra electron shell compared to the sodium atom, which means its valence electrons are further from the nucleus, giving potassium a larger atomic radius. The ionic radius increases in a particular group on moving from top to bottom due to increase in the principle energy shell though the number or electrons in the valence shell remain the same

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3 years ago

Which example best demonstrates the relationship between temperature and pressure? bubbles forming in dough when it is heated bu

Margaret [11]

I think the correct answer from the choices listed above is the first option. The best example that demonstrates the relationship between temperature and pressure would be that <span>bubbles forming in dough when it is heated. Hope this answers the question.</span>

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3 years ago

It is desired to make 1.00 liter of 6.00 M nitric acid from concentrated 16.00 M HNO3.A) How many moles of nitric acid are in 1.

natima [27]

Answer:

A) 6.00 mol.

B) 0.375 L or 375 mL

C) 6.00 M

Explanation:

Hello,

A) In this case, from the definition of molarity, we compute the moles for the given volume and concentration:

$n=M*V=1.00L*6.00mol/L=6.00mol$