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3 years ago

Do this Q7 if someone do I will her or him brainliest

Chemistry

1 answer:

spayn [35]3 years ago

6 0

The average speed :

1. 10.44 m/s

2. 10.42 m/s

3. 9.26 m/s

The distance 100 m have the greatest average speed

<h3>Further explanation</h3>

Given

Distance and time of runner

Required

Average speed

Solution

<em>Average speed : total distance : taotal time</em>

1. d = 100 m, t = 9.58 s

Average speed : 100 : 9.58 = 10.44 m/s

2. d=200 m, t=19.19 s

Average speed : 200 : 19.19 = 10.42 m/s

3. d=400 m, t = 43.18 s

Average speed : 400 : 43.18 = 9.26 m/s

The distance 100 m have the greatest average speed

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Gallium oxide, Ga.Oy, forms when gallium is combined with oxygen. A 1.25 g of Ga is allowed to react with excess oxygen and 1.68

mrs_skeptik [129]

Answer : The chemical formula of a compound is, $Ga_2O_3$

Solution : Given,

Mass of gallium = 1.25 g

Mass of gallium oxide = 1.68 g

Mass of oxygen = Mass of gallium oxide - Mass of gallium

Mass of oxygen = 1.68 - 1.25 = 0.43 g

Molar mass of Ga = 69.72 g/mole

Molar mass of O = 16 g/mole

Step 1 : convert given masses into moles.

Moles of Ga = $\frac{\text{ given mass of Ga}}{\text{ molar mass of Ga}}= \frac{1.25g}{69.72g/mole}=0.0179moles$

Moles of O = $\frac{\text{ given mass of O}}{\text{ molar mass of O}}= \frac{0.43g}{16g/mole}=0.027moles$

Step 2 : For the mole ratio, divide each value of moles by the smallest number of moles calculated.

For Ga = $\frac{0.0179}{0.0179}=1$

For O = $\frac{0.027}{0.0179}=1.5$

The ratio of Ga : O = 1 : 1.5

To make in whole number we multiple ratio by 2, we get:

The ratio of Ga : O = 2 : 3

The mole ratio of the element is represented by subscripts in empirical formula.

The Empirical formula = $Ga_2O_3$

The empirical formula weight = 2(69.72) + 3(16) = 187.44 gram/eq

Now we have to calculate the molecular formula of the compound.

Formula used :

$n=\frac{\text{Molecular formula}}{\text{Empirical formula weight}}$

$n=\frac{187.44}{187.44}=1$

Molecular formula = $(Ga_2O_3)_n=(Ga_2O_3)_1=Ga_2O_3$

Therefore, the chemical of the compound is, $Ga_2O_3$

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3 years ago

What is the mass of 0.5 moles of ammonia, NH3?

Mashcka [7]

Answer:

Mass = 8.5 g

Explanation:

Given data:

Mass of ammonia = ?

Number of moles = 0.5 mol

Solution:

Formula:

Mass = number of moles × molar mass

Molar mass of ammonia = 17 g/mol

By putting values,

Mass = 0.5 mol × 17 g/mol

Mass = 8.5 g

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3 years ago

True/False: The Northern Hemisphere experiences winter when Earth is farthest from the sun.

baherus [9]

Answer:

False

Explanation:

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3 years ago

If only 0.186 g of Ca(OH)2 dissolves in enough water to give 0.230 L of aqueous solution at a given temperature, what is the Ksp

Lilit [14]

Answer:

$Ksp=5.20x10^{-6}$

Explanation:

Hello there!

In this case, according to the solubility equilibrium of calcium hydroxide:

$Ca(OH)_2\rightleftharpoons Ca^{2+}+2OH^-$

Whereas the equilibrium expression is:

$Ksp=[Ca^{2+}][OH^-]^2$

It is firstly necessary to calculate the molar solubility given the grams and volume of the dissolved solute:

$s=\frac{0.186g/(74.09g/mol)}{0.230L}=0.0109M$

Now, according to the Ksp expression, we plug in s as the solubility to obtain:

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Regards!

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3 years ago

A theory should be able to explain the relevant data and lead to correct predictions.

olya-2409 [2.1K]

The correct answer is true

5 0

3 years ago

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