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3 years ago

Elements in the same group/family of the periodic table are similar in what way?

Chemistry

2 answers:

Lera25 [3.4K]3 years ago

8 0

Answer:

D)They have the same number of valance electrons.

Explanation:

The elements in the same group have same number of valance electrons thus have similar properties.

Consider the elements of group two i.e alkaline earth metals. All have two valance electrons and show similar properties.

Magnesium, barium, calcium etc.

All alkaline earth metals form salt with halogens.e.g,

Mg + Cl₂ → MgCl₂

Ba + Br₂ → BaBr₂

Mg + Br₂ → MgBr₂

Ca + Br₂ → CaBr₂

They react with oxygen and form oxides of respective metal.

2Mg + O₂ → 2MgO

2Ba + O₂ → 2BaO

2Ca + O₂ → 2CaO

these oxides form hydroxide when react with water,

MgO + H₂O → Mg(OH)₂

BaO + H₂O → Ba(OH)₂

CaO + H₂O → Ca(OH)₂

With nitrogen it produced nitride,

3Mg + N₂ → Mg₃N₂

3Ba + N₂ → Ba₃N₂

3Ca + N₂ → Ca₃N₂

With acid like HCl,

Mg + 2HCl → MgCl₂ + H₂

Ba + 2HCl → BaCl₂ + H₂

Ca + 2HCl → CaCl₂ + H₂

kobusy [5.1K]3 years ago

8 0

Answer:

C) Six valence electrons, solid, nonmetal

Explanation:

Six valence electrons, solid, nonmetal. Element C is oxygen since it forms the -2 ion and is a gas. All the other elements in that column have six valence electrons, must be a solid and are nonmetals.

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3 years ago

The following data were obtained in a kinetics study of the hypothetical reaction A + B + C → products. [A]0 (M) [B]0 (M) [C]0 (

Vladimir [108]

Answer:

B. First order, Order with respect to C = 1

Explanation:

The given kinetic data is as follows:

A + B + C → Products

[A]₀ [B]₀ [C]₀ Initial Rate (10⁻³ M/s)

1. 0.4 0.4 0.2 160

2. 0.2 0.4 0.4 80

3. 0.6 0.1 0.2 15

4. 0.2 0.1 0.2 5

5. 0.2 0.2 0.4 20

The rate of the above reaction is given as:

$Rate = k[A]^{x}[B]^{y}[C]^{z}$

where x, y and z are the order with respect to A, B and C respectively.

k = rate constant

[A], [B], [C] are the concentrations

In the method of initial rates, the given reaction is run multiple times. The order with respect to a particular reactant is deduced by keeping the concentrations of the remaining reactants constant and measuring the rates. The ratio of the rates from the two runs gives the order relative to that reactant.

Order w.r.t A : Use trials 3 and 4

$\frac{Rate3}{Rate4}= [\frac{[A(3)]}{[A(4)]}]^{x}$

$\frac{15}{5}= [\frac{[0.6]}{[0.2]}]^{x}$

$3 = 3^{x} \\\\x =1$

Order w.r.t B : Use trials 2 and 5

$\frac{Rate2}{Rate5}= [\frac{[B(2)]}{[B(5)]}]^{y}$

$\frac{80}{20}= [\frac{[0.4]}{[0.2]}]^{y}$

$4 = 2^{y} \\\\y =2$

Order w.r.t C : Use trials 1 and 2

$\frac{Rate1}{Rate2}= [\frac{[A(1)]}{[A(2)]}]^{x}[\frac{[B(1)]}{[B(2)]}]^{y}[\frac{[C(1)]}{[C(2)]}]^{z}$

we know that x = 1 and y = 2, substituting the appropriate values in the above equation gives:

$\frac{160}{80}= [\frac{[0.4]}{[0.2]}]^{1}[\frac{[0.4]}{[0.4]}]^{2}[\frac{[0.2]}{[0.4]}]^{z}$

$1 = (0.5)^{z}$

z = 1

Therefore, order w.r.t C = 1

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3 years ago

Why is it commonly believed that carbon dioxide is responsible for global warming? Select 2 options.

monitta

Answer:

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Carbon has a longer average lifetime in the atmosphere.

Explanation:

Today the level of carbon dioxide is higher than at any time in human history. Scientists widely agree that Earth’s average surface temperature has already increased by about 2 F (1 C) since the 1880s, and that human-caused increases in carbon dioxide and other heat-trapping gases are extremely likely to be responsible.

The lifetime in the air of CO2, the most significant man-made greenhouse gas, is probably the most difficult to determine, because there are several processes that remove carbon dioxide from the atmosphere. Between 65% and 80% of CO2 released into the air dissolves into the ocean over a period of 20–200 years.

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Answer:

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Explanation:

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Finally, in the product we will have chiral carbons, so we have to find the absolute configuration for each carbon. On carbon 3 we will have an "R" configuration on carbon 4 we will have also an "R" configuration. (See figure 1)

I hope it helps!

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