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3 years ago

In what way do the atoms in the same row of the Periodic Table increase from left to right?

Chemistry

1 answer:

zheka24 [161]3 years ago

5 0

Answer:

As you move from left to right, the nucleus gains protons. This increases the positive charge of the nucleus and its attractive force on the electrons. At the same time, electrons are added to the atoms as you move from left to right across a period.

Explanation:

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A 100.0 ml sample of 0.10 m ca(oh)2 is titrated with 0.10 m hbr. determine the ph of the solution after the addition of 400.0 ml

WINSTONCH [101]

The balanced equation for the reaction is as follows;
Ca(OH)₂ + 2HBr --> CaBr₂ + 2H₂O
stoichiometry of Ca(OH)₂ to HBr is 1:2
number of Ca(OH)₂ moles reacted - 0.10 mol/L x 0.1000 L = 0.010 mol
Number of HBr moles added - 0.10 mol/L x 0.4000 = 0.040 mol
1 mol of Ca(OH)₂ needs 2 mol of HBr for neutralisation
therefore 0.010 mol of Ca(OH)₂ needs - 0.010 x 2 = 0.020 mol of HBr to be neutralised
but 0.040 mol of HBr has been added therefore number of moles of HBr in excess - 0.040 - 0.020 = 0.020 mol
then pH of the medium can be calculated using the excess H⁺ ions
HBr is a strong acid therefore complete ionization
[HBr] = [H⁺]
[H⁺] = 0.020 mol / (100.0 + 400.0 mL)
= 0.020 mol / 0.5 L
= 0.040 mol/L
pH = -log[H⁺]
pH = - log [0.040 M]
pH = 1.40
pH of the medium is 1.40

8 0

3 years ago

A 3.50 g sample of an unknown compound containing only C , H , and O combusts in an oxygen‑rich environment. When the products h

statuscvo [17]

Explanation:

First, calculate the moles of $CO_{2}$ using ideal gas equation as follows.

PV = nRT

or, n = $\frac{PV}{RT}$

= $\frac{1 atm \times 4.41 ml}{0.0821 Latm/mol K \times 293 K}$ (as 1 bar = 1 atm (approx))

= 0.183 mol

As, Density = $\frac{mass}{volume}$

Hence, mass of water will be as follows.

Density = $\frac{mass}{volume}$

0.998 g/ml = $\frac{mass}{3.26 ml}$

mass = 3.25 g

Similarly, calculate the moles of water as follows.

No. of moles = $\frac{mass}{\text{molar mass}}$

= $\frac{3.25 g}{18.02 g/mol}$

= 0.180 mol

Moles of hydrogen = $0.180 \times 2$ = 0.36 mol

Now, mass of carbon will be as follows.

No. of moles = $\frac{mass}{\text{molar mass}}$

0.183 mol = $\frac{mass}{12 g/mol}$

= 2.19 g

Therefore, mass of oxygen will be as follows.

Mass of O = mass of sample - (mass of C + mass of H)

= 3.50 g - (2.19 g + 0.36 g)

= 0.95 g

Therefore, moles of oxygen will be as follows.

No. of moles = $\frac{mass}{\text{molar mass}}$

= $\frac{0.95 g}{16 g/mol}$

= 0.059 mol

Now, diving number of moles of each element of the compound by smallest no. of moles as follows.

C H O

No. of moles: 0.183 0.36 0.059

On dividing: 3.1 6.1 1

Therefore, empirical formula of the given compound is $C_{3}H_{6}O$ .

Thus, we can conclude that empirical formula of the given compound is $C_{3}H_{6}O$ .

6 0

3 years ago

What type of change is the process of solid ice changing into liquid water?

otez555 [7]

The change is called melting

6 0

3 years ago

What are some remarkable properties of water

frosja888 [35]

Explanation:

Water can dissolve in many things because of it's polarity and surface tension.
Water is the only substance that is lighter in its solid form.

7 0

3 years ago

A compound has the formula X2O3 where x is an unknown element. If the compound is 24.26% oxygen, what element does x represent?

Vinil7 [7]

<h3>Answer:</h3>

Element X is Arsenic (Ar)

<h3>Explanation:</h3>

We are given the compound X₂O₃

The compound is 24.26% Oxygen

We are required to identify element X

<h3>Step 1: Determine the mass of Oxygen in the compound </h3>

Atomic mass of Oxygen is 16.0 g

There are three oxygen atoms in the compound

Therefore;

Mass of oxygen in the compound = 3 × 16

= 48 g

<h3>Step 2: Total mass of the compound </h3>

Total percentage = 100%

But, Oxygen in the compound is 24.26 % and has a mass of 48 g

Therefore;

Mass of the compound = (48 g ÷ 24.26 ) × 100

= 197.857 g

<h3>Step 3 mass of X in the compound </h3>

Since we know the mass of oxygen in the compound and the mass of the compound we can determine the mass of X

Mass of X in the compound = Mass of the compound - Mass of Oxygen in the compound

= 197.857 g - 48 g

= 149.857 g

But there are two atoms of X in the compound.

Therefore, molar mass of X = 149.857 g ÷ 2

= 74.929 g

<h3>Step 4: Identity of element X</h3>

We then we need to identify the element with a molar mass of 74.929 g

Therefore, the element represented above is Arsenic which has an atomic mass of 74.92.

Thus, our compound is Ar₂O₃

5 0

3 years ago