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3 years ago

How do the independent and dependent variables in an experiment compare?

1 answer:

4 0

An independent variable is the variable that is changed or controlled in a scientific experiment to test the effects on the dependent variable.

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Whay happens regularly in fission reaction

lorasvet [3.4K]

Answer:

In nuclear fission, an unstable atom splits into two or more smaller pieces that are more stable, and releases energy in the process. The fission process also releases extra neutrons, which can then split additional atoms, resulting in a chain reaction that releases a lot of energy.

Explanation:

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3 years ago

The balanced equation for the reaction of aqueous Pb(ClO3)2 with aqueous NaI is Pb(ClO3)2(aq)+2NaI(aq)⟶PbI2(s)+2NaClO3(aq) What

ryzh [129]

Answer : The mass of $PbI_2$ precipitate produced will be, 9.681 grams.

Explanation : Given,

Molarity of NaI = 0.210 M

Volume of solution = 0.2 L

Molar mass of $PbI_2$ = 461.01 g/mole

First we have to calculate the moles of $NaI$ .

$\text{Moles of }NaI=\text{Molarity of }NaI\times \text{Volume of solution}=0.210M\times 0.2L=0.042moles$

Now we have to calculate the moles of $PbI_2$ .

The balanced chemical reaction is,

$Pb(ClO_3)_2(aq)+2NaI(aq)\rightarrow PbI_2(s)+2NaClO_3(aq)$

From the balanced reaction we conclude that

As, 2 moles of $NaI$ react to give 1 mole of $PbI_2$

So, 0.042 moles of $NaI$ react to give $\frac{0.042}{2}=0.021$ moles of $PbI_2$

Now we have to calculate the mass of $PbI_2$ .

$\text{Mass of }PbI_2=\text{Moles of }PbI_2\times \text{Molar mass of }PbI_2$

$\text{Mass of }PbI_2=(0.021mole)\times (461.01g/mole)=9.681g$

Therefore, the mass of $PbI_2$ precipitate produced will be, 9.681 grams.

6 0

4 years ago

List the polyatomic elements

kvasek [131]

Answer:

Phosphorus, Sulfur, and Selenium are the only polyatomic elements.

Hydrogen, Nitrogen, Oxygen, Fluorine, Chlorine, Bromine, and Iodide are all diatomic elements.

4 0

3 years ago

2 of the important properties of gases. SaveStylesFormat Instructions

lyudmila [28]

Gases have three characteristic properties: (1) they are easy to compress, (2) they expand to fill their containers, and (3) they occupy far more space than the liquids or solids from which they form. An internalcombustion engine provides a good example of the ease with which gases can be compressed.

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4 years ago

A 15.0 gram unknown piece of metal at 99°C is added to 75 grams of water at 23°C. The final temperature of the metal and water i

Nina [5.8K]

By law of conservation of energy, the amount of heat lost by the metal should be equal to the amount of heat gained by water. That is, the change in energy (expressed in enthalpies) should be equal:

- (ΔH)metal = (ΔH)water

Take note of the negative sign in front of (ΔH)metal, this means that heat is lost by this metal.

Where ΔH or change in enthalpy is:

ΔH = m Cp (T2 – T1)

So,

- 15 g (Cp) (23 °C – 99 °C) = 75 g (4.18 J/g * °C) (26 °C – 23 °C)

1,140 Cp = 940.5

Cp = 0.825 J/g * °C (ANSWER)

6 0

3 years ago