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1 year ago

Match each element to the number of electrons in its valence shell.

Chemistry

1 answer:

irinina [24]1 year ago

6 0

Answer:

C: 4

H: 1

Mg: 2

O : 6

Explanation:

You can quickly find out the number of valence electrons by looking at where the element is on the periodic table and referring to the table that is attached.

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A ------------ ----------------- is the dying out of a large number of species on a global scale

ziro4ka [17]

Answer:

Extinction event or sometimes known as Mass extinction

Explanation:

These events typically are typically widespread and rapid decrease in the biodiversity (which takes into account spread and existence of current species). The worst mass extinction was Permian–Triassic extinction where over 90% of species of organisms vanished.

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3 years ago

Why is the metric system the preferred system of measurement for science

Nikolay [14]

In is a lot easier because it uses 10s.

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4 years ago

Read 2 more answers

In the reaction, A → Products, the rate constant is 3.6 × 10−4 s−1. If the initial concentration of A is 0.548 M, what will be t

Arada [10]

Answer:

$\large\boxed{\large\boxed{0.529M}}$

Explanation:

Since the <em>rate constant</em> has units of <em>s⁻¹</em>, you can tell that the order of the reaction is 1.

Hence, the rate law is:

$r=d[A]/dt=-k[A]$

Solving that differential equation yields to the well known equation for the rates of a first order chemical reaction:

$[A]=[A]_0e^{-kt}$

You know [A]₀, k, and t, thus you can calculate [A].

$[A]=0.548M\times e^{-3.6\cdot 10^{-4}/s\times99.2s}$

$[A]=0.529M$

7 0

4 years ago

A plant extract can be obtained with organic solvents such as acetone or ethyl alcohol, and is composed of plant pigments such a

prohojiy [21]

Answer:

Here's what I get

Explanation:

A plant extract is a mixture because it contains different substances: acetone or ethanol, chlorophylls A and B, carotene and xanthophylls.

It is homogeneous because it is a solution. There is only one phase: the liquid phase. You cannot see the pigments as separate phases.

You can separate the pigments by paper, thin layer, or column chromatography.

Many schools use paper chromatography, because paper is cheap.

As the mixture of pigments follows the solvent up the paper, they separate into different coloured bands according to their attractive forces to the cellulose in the paper.

The chlorophylls are strongly attracted to the paper, so they don't travel very far.

The nonpolar carotene molecules have little attraction to the polar cellulose, so they are carried along by the solvent front.

8 0

3 years ago

Predict the reactivity of silicon in water relative to that of sodium, magnesium, and aluminium. Explain your answer. How does t

Inessa [10]

Answer:

See explanation

Explanation:

The reactivity of metals has a lot to do with their position in the electrochemical series. However, it is also known that metallic character decreases across the period. This implies that as we move from left to right along the periodic table. Sodium, magnesium, aluminum and silicon continues to decrease in metallic character. As a matter of fact, silicon is a metalloid and not a pure metal.

Sodium reacts with cold water to give a vigorous reaction,magnesium and aluminium reacts with steam at red heat.

Silicon does not react with water, even as steam, under normal conditions.

5 0

3 years ago