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3 years ago

Please answer these true or false questions.

1 answer:

8 0

1. False, the water being stored behind the dam has potential energy until it begins to flow through the dam (it is then converted to kinetic energy).

2. True

3. True

Hope this helped! :)

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(40 Points) Complete, balance, compute the amounts of the products assuming 100% yield. 10g Na + 10g Oxygen.

Lilit [14]

13.5g

Explanation:

Given parameters:

Mass of Na = 10g

Mass of O₂ = 10g

Unknown:

Mass of products formed = ?

Balanced equation = ?

Solution:

The balanced chemical equation is shown below:

4Na + O₂ ⇒ 2Na₂O

In any reaction, the specie in short supply determines the extent of the reaction.

This reaction is not an exclusion. We need to first determine the specie in short supply and use it to estimate the amount of product since we have a 100% yield which signifies that all was used up.

let us convert to moles;

Number of moles of Na = $\frac{mass }{molar mass} = \frac{10}{23}$ = 0.435mole

Number of moles of O₂ = $\frac{mass}{molar mass} = \frac{10}{32}$ = 0.313mole

From the given equation;

4 moles of Na requires 1 mole of O₂;

0.435 moles of Na will require $\frac{0.435}{4}$ = 0.11 moles

But the given amount O₂ is 0.313, this is an excess of 0.313 - 0.11 = 0.203moles

We see that Na is the limiting reagent;

4 moles of Na gives 2 mole of Na₂O

0.435 moles of Na will give $\frac{0.435 x 2 }{4}$ = 0.22 moles

Mass of Na₂O = number of moles x molar mass = 62 x 0.22 = 13.5g

learn more:

Number of moles brainly.com/question/1841136

#learnwithBrainly

5 0

3 years ago

What is wrong with the way that the hypothesis, “Chocolate may cause pimples”, is written?

DaniilM [7]

Answer:

More sweet and cute with the little ones on the surface and a little more

8 0

3 years ago

Read 2 more answers

I WILL MARK YOU BRAINLIST PLEASE HELP

tekilochka [14]

Answer: See below

Explanation: a. The mass of an element is composed of:

protons: 1 amu each

neutrons: 1 amu each

electrons: 0 amu each

Only the protons and neutrons are counted in the atomic mass of an element

b. Electrons are assigned a mass of 0. They do have a mass, but it is exceedingly small compared to the protons and neutrons, so they are left out of the calculation of an element's mass.

c. An element becomes unstable if the neutrons exceed the protons by a certain ratio, dependent on the element.

7 0

2 years ago

What is the total pressure (in atm) inside of a vessel containing N2 exerting a partial pressure of 0.256 atm, He exerting a par

Bezzdna [24]

Answer: Total pressure inside of a vessel is 0.908 atm

Explanation:

According to Dalton's law, the total pressure is the sum of individual partial pressures. exerted by each gas alone.

$p_{total}=p_1+p_2+p_3$

$p_{N_2}$ = partial pressure of nitrogen = 0.256 atm

$p_{He}$ = partial pressure of helium = 203 mm Hg = 0.267 atm (760mmHg=1atm)

$p_{H_2}$ = partial pressure of hydrogen =39.0 kPa = 0.385 atm (1kPa=0.00987 atm)

Thus $p_{total}=p_{H_2}+p_{He}+p_{H_2}$

$p_{total}$ =0.256atm+0.267atm+0.385atm =0.908atm

Thus total pressure (in atm) inside of a vessel is 0.908

8 0

3 years ago

Read 2 more answers

Two samples of potassium iodide are decomposed into their constituent elements. The first sample produced 13.0g of potassium and

Leona [35]

Answer:

79.43kg

Explanation:

To adequately solve this problem, we should know the law of constant composition. This is a pointer to the fact that no matter the type of sample, the percentage compositions of potassium and iodine still remains the same. We can use these masses to get a formula and we would know the percentage compositions in whatever mass we are dealing with.

First of all, we add the masses in the first sample. 13 + 42.3 = 55.3

Hence, the percentage composition of the potassium is 13/55.3 * 100 = 23.51%

The percentage composition of the iodine is = 100 - 23.51 = 76.49%

Now, we need to get the formula of the compound. We can get this by dividing the percentage compositions with the atomic masses. The atomic mass of potassium and iodine is 39 and 127 respectively.

Potassium = 23.51/39 =0.603

Iodine = 76.49/127 = 0.602

We then divide by the smaller value to get the formula and this shoes our formula is KI

We can see they have a ratio of 1 to 1, meaning one atom of potassium to one atom of iodine. This further confirms the percentage compositions of 23.5 to 76.5

Now to get the mass of iodine yielded, let us say the mass is xkg

This means x/(x + 24.4) * 100 = 76.5

100x = 76.5( x + 24.4)

100x = 76.5x + 1866.6

100x - 76.5x = 1866.6

23.5x = 1866.6

x = 1866.6/23.5 = 79.43kg

4 0

2 years ago