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yarga [219]
3 years ago
15

He predicted an element with an atomic weight between 65 (zinc) and 75 (arsenic) with a valence similar to aluminum that he name

d ekaboron. This element was discovered in 1879. What is this element:?
Chemistry
1 answer:
skad [1K]3 years ago
3 0

Answer:

Scandium

Explanation:

Mendeleev played an important role in the development of the modern periodic table. His periodic table was filled with gaps. He said that these gaps were elements that were yet to be discovered. He rightly predicted many elements which have now been discovered and fitted in their proper places in the periodic table.

He used the prefix ''eka'' to refer to elements whose properties were alike but were yet to be discovered at that time.

The compound named ekaboron which he predicted to have an atomic weight between 65 (zinc) and 75 (arsenic) with a valence similar to aluminum was later discovered in 1879 and properly named scandium.

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Iodine is 80% 127I, 17% 126I, and 3% 128I. Calculate the average atomic mass of Iodine.
trasher [3.6K]
<h3>The average atomic mass of Iodine : 126.86 amu</h3><h3>Further explanation</h3>

Given

80% 127I, 17% 126I, and 3% 128I.

Required

The average atomic mass

Solution

The elements in nature have several types of isotopes

Atomic mass is the average atomic mass of all its isotopes

Mass atom X = mass isotope 1 . % + mass isotope 2.% + ... mass isotope n.%

Atomic mass of Iodine = 0.8 x 127 + 0.17 x 126 + 0.03 x 128

Atomic mass of Iodine = 101.6 + 21.42 + 3.84

Atomic mass of Iodine = 126.86 amu

6 0
3 years ago
K3PO4(aq)+MgCl2(aq)⟶
Wittaler [7]

Answer:

6KCl(aq) +  Mg3(PO4)2(s)  ...  balanced equation

Explanation:

7 0
2 years ago
10. Lead nitrate solution mixed with sodium sulfate solution forms lead sulfate as a
Leviafan [203]

Answer:

88%.

Explanation:

The percentage yield of lead sulfate in this experiment is 88% if 2.53 is divided by 2.85 and multiply by 100. The percentage yield can be calculated when the experimental yield is divided by theoretical yield and then multiply by 100. The percentage yield tells us about the actual yield that is gained in the end of experiment which is lower than theoretical yield.

8 0
3 years ago
How are diffusion and osmosis different?
elena55 [62]
Osmosis is about the movement of water molecules and diffusion is about the movement of substances
8 0
3 years ago
2 HI(g) ⇄ H2(g) + I2(g) Kc = 0.0156 at 400ºC 0.550 moles of HI are placed in a 2.00 L container and the system is allowed to rea
Alex_Xolod [135]

<u>Answer:</u> The concentration of hydrogen gas at equilibrium is 0.0275 M

<u>Explanation:</u>

Molarity is calculated by using the equation:

\text{Molarity}=\frac{\text{Number of moles}}{\text{Volume of solution (in L)}}

Moles of HI = 0.550 moles

Volume of container = 2.00 L

\text{Initial concentration of HI}=\frac{0.550}{2}=0.275M

For the given chemical equation:

                          2HI(g)\rightleftharpoons H_2(g)+I_2(g)

<u>Initial:</u>                  0.275

<u>At eqllm:</u>           0.275-2x      x         x

The expression of K_c for above equation follows:

K_c=\frac{[H_2][I_2]}{[HI]^2}

We are given:

K_c=0.0156

Putting values in above expression, we get:

0.0156=\frac{x\times x}{(0.275-2x)^2}\\\\x=-0.0458,0.0275

Neglecting the negative value of 'x' because concentration cannot be negative

So, equilibrium concentration of hydrogen gas = x = 0.0275 M

Hence, the concentration of hydrogen gas at equilibrium is 0.0275 M

4 0
3 years ago
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