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2 years ago

Compare the properties of elements in groups 17 and group 18. Make sure to cover the following points:

Chemistry

2 answers:

Andre45 [30]2 years ago

8 0

Answer:

Letter: C

explanation:

sdas [7]2 years ago

3 0

Answer:

a) Explain why:

(i) All the elements of a group have similar chemical properties.

(ii) All the elements of a period have different chemical properties.

(b) The atomic radii of three elements X, Y and Z of a period of the periodic table are 186 pm, 104 pm and 143 pm respectively. Giving a reason arrange these elements in the increasing order of atomic number in the period.

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Element M has two isotopes,^104M and ^106M.

snow_lady [41]

To calculate atomic mass, you have to take to weighted average of the isotopes' masses. What that means is M = RA*106 + (1 – RA)*104, where RA is relative abundance expressed in decimal form. If you simplify the right side of that equation, you get M = 2*RA + 104. Doing a little more algebra yields RA = (M –104)/2 = (104.4 – 104)/2 = 0.4 / 2 = 0.2, which is 20%. So the answer is B.

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3 years ago

The chemical equation for a reaction between K2Cr2O7 and HCl is shown. K2Cr2O7 + 14HCl → 2CrCl3 + 2KCl + 3Cl2 + 7H2O

guapka [62]

Answer: The correct answer is Option b.

Explanation:

Oxidizing agent is defined as the chemical reagent which helps the other chemical compound to get oxidized and itself gets reduced. The oxidation state for these species gets reduced because they are undergoing reduction reaction.

For the given chemical equation:

$K_2Cr_2O_7+14HCl\rightarrow 2CrCl_3+2KCl+3Cl_2+7H_2O$

Oxidation state of Chromium is getting reduced from +6 to +3 and oxidation state of chlorine getting increased from -1 to 0.

Hence, $K_2Cr_2O_7$ acts like and oxidizing agent because it is itself getting reduced to $CrCl_3$

Therefore, the correct answer is Option b.

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3 years ago

Viruses

Lelechka [254]

Answer:

just see it it will help trust me its my school work

Explanation:

Download pdf

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2 years ago

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Our solar system formed from a

ankoles [38]

Our solar system formed about 4.5 billion years ago from a dense cloud of interstellar gas and dust. The cloud collapsed most likely due to a shockwave form a nearby exploding start called a supernova

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2 years ago

How many moles in 4.93 x 10E23 atoms of silver?

leva [86]

<h3>Answer:</h3>

0.819 mol Ag

<h3>General Formulas and Concepts:</h3>

Math

Pre-Algebra

Order of Operations: BPEMDAS

Brackets
Parenthesis
Exponents
Multiplication
Division
Addition
Subtraction

Left to Right

Chemistry

Atomic Structure

Avogadro's Number - 6.022 × 10²³ atoms, molecules, formula units, etc.

Stoichiometry

Using Dimensional Analysis

<h3>Explanation:</h3>

Step 1: Define

4.93 × 10²³ atoms Ag

Step 2: Identify Conversions

Avogadro's Number

Step 3: Convert

Set up: $\displaystyle 4.93 \cdot 10^{23} \ atoms \ Ag(\frac{1 \ mol \ Ag}{6.022 \cdot 10^{23} \ atoms \ Ag})$
Divide: $\displaystyle 0.818665 \ mol \ Ag$

Step 4: Check

Follow sig fig rules and round. We are given 3 sig figs.

0.818665 mol Ag ≈ 0.819 mol Ag

8 0

2 years ago