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Anika [276]
3 years ago
15

Identify each element below, and give the symbols of the other elements in its group:

Chemistry
1 answer:
nikdorinn [45]3 years ago
3 0

Answer:

In explanation

Explanation:

a. Selenium, atomic number 34

Argon is 18, adding the other electrons gives 34.

Other elements include: oxygen O , Sulphur S , Tellurium Te and Polonium Po

b. Hafnium, element 72

Xe is 54, adding the other electrons makes the total 72.

Other elements; Titanium Ti, Zirconium Zr, Rutherfordium Rf

c. Manganese, element 25

Other group members are Technetium Tc , Rhenium Re and Bohrium Bo

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Why methyl orange in basic medium is yellow and why it is red in acidic medium?​
Sholpan [36]
Methyl orange shows red color in acidic medium and yellow color in basic medium. Because it changes color at the pKa of a mid strength acid, it is usually used in titration for acids. Unlike a universal indicator, methyl orange does not have a full spectrum of color change, but it has a sharp end point.
7 0
3 years ago
The modern periodic table is arranged in order of increasing. true or false
qaws [65]

Answer:

Increasing atomic number - True

Explanation:

The modern table is based on Mendeleev’s table, except the modern table arranges the elements by increasing atomic number instead of atomic mass.

The Atomic number is the number of protons in an atom, and this number is unique for each element. For example, Hydrogen has an atomic number of 1, Calcium has an atomic number of 20.

In the modern periodic table the elements are further arranged into:

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4 0
3 years ago
Which of these is indication that a chemical reaction has occurred?
trasher [3.6K]
B.melting of a substance
3 0
3 years ago
Read 2 more answers
Decide whether the compound is ionic or molecular, if you can.
mestny [16]

Answer:

Molecular solid

Explanation:

A molecular solid has a low melting point, they are soft and do not conduct electricity.

We have been told in the question that the solid does not really dissolve in water and it's solution does not improve the electrical conductivity of water. Hence, it must be a molecular solid.

7 0
3 years ago
A chemist adds 485 mL of a 0.0025 mol/L calcium sulfate solution to a reaction flask. Calculate the mass in grams of calcium sul
viva [34]

Answer : The mass in grams of calcium sulfate is 0.16 grams.

Explanation :

Molarity : It is defined as the number of moles of solute present in one litre of solution.

Formula used :

Molarity=\frac{\text{Mass of solute}\times 1000}{\text{Molar mass of solute}\times \text{Volume of solution}}

Solute is, CaSO_4

Given:

Molarity of CaSO_4 = 0.0025 mol/L

Molar mass of CaSO_4 = 136 g/mole

Volume of solution = 485 mL

Now put all the given values in the above formula, we get:

0.0025=\frac{\text{Mass of }CaSO_4\times 1000}{136\times 485}

\text{Mass of }CaSO_4=0.16g

Thus, the mass in grams of calcium sulfate is 0.16 grams.

6 0
3 years ago
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