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3 years ago

Two products of stars

Chemistry

1 answer:

Andre45 [30]3 years ago

4 0

Two properties of a star is luminosity and temperature.

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44.8% of a 250. mL acid solution is used in an experiment, what volume of acid (in mL) was used?

postnew [5]

Answer:

112 mL

Explanation:

The formula for percent by volume is

$\text{Percent by volume} = \dfrac{\text{Volume of solute}}{\text{Volume of solution}}\times 100 \, \%$

If you have 250 mL of a solution that is 44.8 % v/v,

$\begin{array}{rcl}44.8\, \% & = & \dfrac{\text{Volume of solute}}{\text{250 mL}}\times 100 \, \%\\\\44.8 \times \text{ 250 mL} & = & \text{Volume of solute} \times 100\\\text{Volume of solute} & = & \dfrac{44.8 \times 250\text{ mL}}{100}\\\\ & = & \textbf{112 mL}\\\end{array}$

7 0

3 years ago

How many miles are there in 20g of KClO3 (k=39 Cl=35.5 O=16)

SashulF [63]

<h3>Answer:</h3>

0.144 moles

<h3>Explanation:</h3>

The relationship between mass of a compound, number of moles and molar mass of the compound is given by;
Number of moles = Mass ÷ Molar mass
Molar mass is equivalent to the relative formula mass of the compound that is calculated the atomic masses of the elements making the compound.

In this case;

Our compound, KClO3 will have a molar mass of;

= 39 + 35.5 + 4(16)

= 138.5 g/mol

Mass of KClO3 is 20 g

Therefore;

Number of moles = 20 g ÷ 138.5 g/mol

= 0.144 moles

Thus, the number of moles in 20 g of KClO3 is 0.144 moles

4 0

3 years ago

A ground water tank has its height 2m. Calculate the pressure at its bottom when it is completely filled with water.

Law Incorporation [45]

The pressure at the bottom : 19600 N/m²

<h3>Further explanation</h3>

Given

A ground water tank has its height 2m

Required

The pressure at its bottom

Solution

Hydrostatic pressure is the pressure caused by the weight of a liquid.

The weight of a liquid is affected by the force of gravity.

The hydrostatic pressure of a liquid can be formulated:

$\large{\boxed{\bold {P_h ~ = ~ \rho.g.h}}$

Ph = hydrostatic pressure (N / m², Pa)

ρ = density of liquid (kg / m³)

g = acceleration due to gravity (m / s²)

h = height / depth of liquid surface (m)

ρ = density of water (kg / m³) = 1000

g = acceleration due to gravity = 9.8 m/ sec²

The pressure

$\tt P=1000\times 9.8\times 2=19600~N/m^2$

6 0

3 years ago

In a compound, such as CH3OH, how determine which is the central atom?

svetlana [45]

Answer:

Choose the least electronegative atom other than H.

Explanation:

A Lewis structure consists of <em>terminal atoms</em> and one or more <em>central atoms</em>.

H can be <em>only a terminal atom</em> because it can form only one bond.

So the central atom must be either C or O.

The central atom is the less electronegative atom: C.

So, start the Lewis structure with a central C atom.

Then attach an O atom to get C-O.

Finally, attach the H atoms.

The condensed formula often gives you a clue where they go.

The formula CH₃OH implies that there are 3 H atoms on C and one on O.

The connectivity of the atoms is then as in the diagram below.

3 0

3 years ago

How many moles of ammonia are produced when 5.0 moles of hydrogen react with excess nitrogen? Use this balanced equation for the

wel

3 mol H₂ → 2 mol NH₃

5 mol H₂ → x mol NH₃

x=2*5.0/3=3.3

n(NH₃)=3.3 mol

7 0

3 years ago