2. A car travels at 65 miles/hr for 4.5 hours from Houston to Dallas. What is the

Given: 4Na + O2 → 2Na2O In this chemical reaction, how many moles of Na2O will be produced if 2.90 moles of Na react completely?

crimeas [40]

Since we already have the balanced equation, we know that the ratio between $Na:Na_{2}O$ is $4:2$ respectively.

So then we can set up a proportion to find the number of moles produced when 2.90 moles of Na react completely:

$\frac{4mol_{Na}}{2mol_{Na_{2}O}} =\frac{2.90mol_{Na}}{xmol_{Na_{2}O}}$

Then we cross multiply and solve for x:

$4x=5.8$

$x=1.45$

Therefore, we know that when 2.90 moles of Na react completely, there are 1.45 moles of $Na_{2}O$ that are produced.

3 0

3 years ago

A particular first-order reaction has a rate constant of 1.35 × 102 s-1 at 25.0°C. What is the magnitude of k at 95.0°C if Ea =

never [62]

Answer:

k ≈ 9,56x10³ s⁻¹

Explanation:

It is possible to solve this question using Arrhenius formula:

$ln\frac{k2}{k1} = \frac{-Ea}{R} (\frac{1}{T2} -\frac{1}{T1} )$

Where:

k1: 1,35x10² s⁻¹

T1: 25,0°C + 273,15 = 298,15K

Ea = 55,5 kJ/mol

R = 8,314472x10⁻³ kJ/molK

k2 : ???

T2: 95,0°C+ 273,15K = 368,15K

Solving:

$ln\frac{k2}{k1} = 4,257$

$\frac{k2}{k1} = 70,593$

${k2} = 9,53x10^3 s^{-1}$

k ≈ 9,56x10³ s⁻¹

I hope it helps!

5 0

3 years ago

A sample of an uranium compound is found to be losing mass gradually. Explain what is happening to the sample.

yan [13]

Answer:

The uranium in the sample of the compound is radioactive

Explanation:

Some atoms can split on their own. Some split when bombarded by energetic particles. Such atoms are said to be radioactive.

Radioactivity is borne out of the drive of an atom to reach stabillity. Every atom have a specific neutron/proton ratio which ensures stability of the nucleus. A nucleus with a stability ratio different from that which makes it stable will become unstable and split into one or more other nuclei with emissons of energetic particles.

Note: neutrons and protons dictates the mass of an atom. They are located in the nucleus which is the site for nuclear radioactive reactions.

4 0

3 years ago

13.0 g NaHSO4 is dissolved in water to make a 2.00 L solution what is the molarité

Sati [7]

Answer:

0.054 M

Explanation:

1 mol NaHSO4 -> 120 g

x ->13 g

x= 0.108 mol NaHSO4

M= mol solute/ L solution

M= 0.108 mol NaHSO4/ 2.00L

M= 0.054 M

8 0

3 years ago

Which statement is a valid conclusion about the activation energy of the reverse reaction if the forward reaction is exothermic?

babunello [35]

Answer:

e) The activation energy of the reverse reaction is greater than that of the forward reaction.

Explanation:

Activation energy is the minimum amount of energy that is required by the reactants to start a reaction.
An exothermic reaction is a reaction that releases heat energy to the surrounding while an endothermic reactions is a reaction that absorbs heat from the surrounding.
In reversible reactions, when the forward reaction is exothermic it means the reverse reaction will be endothermic, therefore the reverse reaction will have a higher activation energy than the forward reaction. The activation energy of the reverse reaction will be the sum of the enthalpy and the activation energy of the forward reaction.

4 0

3 years ago