Answer:
Explanation:
1. Convert decagrams to grams
2. Convert grams to decigrams
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A 2.000 g sample of CoCl2.xH2O is dried in an oven. When the anhydrous salt is removed from the oven, its mass is 1.565 g. What
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Answer:
The required hybridization for a central atom that have:
a tetrahedral arrangement of electron pairs is
a trigonal planar arrangement of electron pairs is
a linear arrangement of electron pairs is
Explanation:
From the given information:
The required hybridization for a central atom that have:
a tetrahedral arrangement of electron pairs is
a trigonal planar arrangement of electron pairs is
a linear arrangement of electron pairs is
Hybridization is the mixing and blending of two or more pure atomic orbitals ( s, p and d) to forma two or more hybrid atomic orbitals that are identical in shape and energy e. sp ,sp² , sp³, sp³d hybrid orbitals.
Examples:
Tetrahedral
In CH₄ , carbon C is the central atom.
A 2s electron is excited from the ground state of boron 1s²2s²2p² to one of the empty orbitals to 2p to give the excited state 1s²2s²2p³.
In the excited state of carbon, the 2-s orbital can be mixed with the 2p orbitals in three ways : sp³, sp² and sp hybridization. For the formation of four sp³ hybrid orbitals, the 2s orbital are mixed with all the three p orbitals. The four sp³ hybrid orbitals are tetrahedrally arranged with a bond angle of 109.5⁰
Trigonal Planar
In BF₃ , Boron B is the central atom
A 2s electron is excited from the ground state of boron 1s²2s²2p¹ to one of the empty orbitals to 2p. The 2s orbital is then mixed with two orbitals of 2p to form three sp² hybrid orbitals that are trigonal planar arranged in the plane in order to minimize repulsion. They bonds between them form an equal strength and with bond angles of 120⁰
Linear arrangement:
In BeCl₂, Be is the central atom
To provide the unpaired electrons for covalent bonds a 2s electron is excited to a 2p orbital. Thereafter, the two atomic orbitals hybridize to give two identical orbitals called sp hybrid orbitals. The sigma bond for,ed are equal in bond lengths and form a bond angle of 180°
The rate at which radioactive substances disintegrate is a constant for a
given radioactive material.
- <u>The fossil is 710 million years old</u>.
Reasons:
The half-life of a radioactive material is the time it takes half of the nucleus
of a radioactive material to disintegrate into other forms of materials
through the given off of energy and particles.
The half life of Uranium 235 = 710 million years
The product of the decay of Uranium 235 = Lead 207
The mass of Uranium 235 in the fossil = 4 micrograms
The mass of Lead 207 in the sample = 4 micrograms
Therefore, the mass of Lead 207 in the fossil is equal to the mass of
Uranium 235, therefore, a minimum of half of the Uranium 235 has
decomposed, which gives;
The time of decomposition of the Uranium 235 = 1 Half life = 710 million years
The age of the fossil = The time in which the Uranium has been
decomposing = The time of decomposition = 1 half life of Uranium 235 = 710
million years
- <u>The age of the fossil = 710 million years</u>
Using the formula for half-life, we get;
The fossil contains initially only Uranium 235 with a minimum mass of 4 mg
+ 4 mg = 8 mg, which gives;
N₀ = 8 mg
N(t) = The current mass of Uranium 235 = 4 mg
= 710 million years
Therefore;
t = 710
- <u>The age of the fossil, </u><u><em>t</em></u><u> = 710 million years</u>
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