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3 years ago

How does a scientist explain something when a controlled experiment cannot be carried out

1 answer:

7 0

<span> We look for evidence. There are numerous natural phenomenon that we can't observe happening in real-time because they happen over large time scales, or large spatial scales. But we can observe the effects of these phenomenon and make predictions about what other effects we should see. </span>

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Please Help! Asap! :)

yaroslaw [1]

I need details to solve for you

3 0

3 years ago

Read 2 more answers

Interstellar space has an average temperature of about 10 K , and an average density of hydrogen atoms of about one hydrogen ato

Bas_tet [7]

Answer:

$2.2508\times 10^{19} m$ meter the mean free path of hydrogen atoms in interstellar space.Explanation:

The mean free path equation is given as:

$\lambda =\frac{1}{\sqrt{2}\pi d^2 n}$

Where"

d = diameter of hydrogen atom in meters

n = number of molecules per unit volume

We are given: d = 100 pm = $100\times 10^{-12}= 10^{-10} m$

$n = 1 m^{-3}$

$\lambda =\frac{1}{\sqrt{2}\pi (10^{-10} m)^2\times 1 m^{-3}}$

$\lambda =2.2508\times 10^{19} m$

$2.2508\times 10^{19} m$ meter the mean free path of hydrogen atoms in interstellar space.

7 0

3 years ago

How many valence electrons does calcium want to gain or lose to have a full outer shell?

grandymaker [24]

Explanation:

For example, Identify the number and type of ions formed in a reaction of calcium and carbon. Step 1: Determine the number of valence electrons for each element and whether the element loses or gains electrons. Calcium has 2 valence electrons and is a metal so it will give up two electrons.

4 0

3 years ago

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When 40.5 g of Al and 212.7 g of Cl2 combine in the reaction: 2 Al (s) + 3 Cl2 (g) --> 2 AlCl3 (s) c) How many moles of the e

sineoko [7]

Answer:

The answer to your question is 1.49 mol of Cl₂

Explanation:

Data

mass of Al = 40.5 g

mass of Cl₂ = 212.7 g

moles of excess reactant = ?

- Balanced chemical reaction

2 Al(s) + 3Cl₂(g) ⇒ 2AlCl₃

Process

a) Calculate the molar mass of the reactants

molar mass of Al = 2 x 26.98 = 53.96 g

molar mass of Cl₂ = 6 x 35.45 = 212.7 g

b) Calculate the theoretical proportion Al/Cl₂ = 53.96/212.7 = 0.254

Calculate the experimental proportion Al/Cl₂ = 40.5/212.7 = 0.19

As the experimental proportion is lower than the theoretical proportion we conclude that the limiting reactant is Aluminum.

c) Calculate the grams of excess reactant

53.96 g of Al ------------------ 212.7 g of Cl₂

40.5 g of Al ------------------- x

x = (40.5 x 212.7) / 53.96

x = 8614.35 / 53.96

x = 159.64 g of Cl₂

Excess Cl₂ = 212.7 - 159.64

= 53.057 g

d) Calculate the moles of Cl

35.45 g of Cl ----------------- 1 mol

53.057 g of Cl --------------- x

x = (53.057 x 1)/35.45

x = 1.49 mol of Cl₂

6 0

3 years ago

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What volume of chlorine gas at 27 °C, 812 mmHg, is required to react with an excess of carbon disulfide so that 5.00kJ of heat i

Kamila [148]

Answer:

The correct answer is 1.21 L.

Explanation:

Based on the given information, the reaction will be,

CS2 (l) + 3Cl2 (g) ⇒ CCl4 (l) + S2Cl2 (l)

By using the standard values of the substances, the standard enthalpy of the reaction is,

ΔH° = [(-139.5) + (-58.5) – 0 – (87.3)] kJ/mol

= -285.3 kJ/mol

The amount of heat evolved for 3 moles of chlorine reacted us 285.3 kJ.

Now the number of moles of chlorine needed to react to produce 5.00 kJ is,

= 5.00 kJ × 3 mol Cl2/285.3 kJ

= 0.0526 mol Cl2

Now the volume of chlorine gas at 27degree C and 812 mmHg will be,

Volume = 0.0526 mol Cl2 × 0.0821 Latm/mol K × 300 K/ 1.07 atm

= 1.21 L

4 0

3 years ago