Why is it possible to collect hydrogen gas over water?

Answer:

Explanation:If the products of a reaction have higher energy than the reactants, then the reaction...

Answer:

A substance that has a fixed chemical composition throughout is called a pure substance such as water, air, and nitrogen. A pure substance does not have to be of a single element or compound.

Explanation:

Compound: A substance that contains more than one element

pure substance: is made up of one substance made up of only one type of molecule

Answer:

the ability of a compound to dissolve

Explanation:

salt dissolves in water so it would be soluble.

oil does not dissolve in water so it is not soluble

Answer: the answer should be A the first one

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Answer:

activity series is a list of substances ranked in order of relative reactivity.

For example, magnesium metal can displace hydrogen ions from solution. So magnesium is more reactive than hydrogen:

Mg(s) + 2H⁺(aq) → H₂(g) + Mg²⁺(aq)

Zinc metal can also displace hydrogen ions from solution:

Zn(s) + 2H⁺(aq) → H₂(g) + Zn²⁺(aq)

so zinc is also more active than hydrogen.

But magnesium metal can displace zinc ions from solution:

Mg(s) + Zn²⁺(aq) → Zn(s) + Mg²⁺(aq)

so magnesium is more active than zinc.

The activity series including these elements would be Mg > Zn > H.

Chemists have built up a complete activity series in a similar way.

The most active metals are at the top of the table; the least active are at the bottom.

Any metal that is higher in the series will displace a metal that is below it in a

The knowledge of the activity series in choosing which metal to build things with because; it provides a basis for determining which metal ion is able to displace the other upon chemical interaction.

The choice of building material is a very important design consideration.

This variation is carefully quantified by the position of metals on the activity series.

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A subshell which is 100% full or 50% full is more stable than subshells which are partially filled with a number of electrons less than or greater than half the number of electrons which can be held by the subshell.

Explanation:

Answer:

chromosome

Explanation:

Answer:

Most of the DNA in all animals, humans, and plants is found in the cell nucleus. Humans, animals and plants contains both DNA and RNA in the cell nucleus and they have to be present in all because every organisms structure and function directly depends upon them.

Explanation:

3. both covalent and ionic

Sodium Phosphate is an ionic compound formed by two ions, Sodium Na+ and Phosphate PO−3 . In order for these two polyatomic ions to bond the charges must be equal and opposite. Therefore, it will take three +1 sodium ions to balance the one -3 phosphate ion. However, polyatomic ions are held together by covalent bonds, so this compound contains both ionic and covalent bonds.

Answer:

ACID RAIN

Explanation:

duh

Answer:

Lithium has 1 valence electron, Sulfur has 6

A is oxidized, B is reduced

A is reducing agent, B is oxidizing agent

Explanation:

when an atom loses electrons, it is oxidized

when an atom gains electrons, it is reduced (almost think of when you add a negative number to a positive number, the positive number gets smaller or is reduced)

Answer:

There are 10 neutrons

Explanation:

Because the atomic number is 8 and the isotope number is 18 (which is the collective protons and neutrons), we can do

18-8=10

Answer:

10

Explanation:

8 proton because it is oxygen

10 neutron because 18-8

Answer:

ok you got it you just need to add.

Explanation:

add 5 times and she what you get.

Answer:

The convection zone :)

Answer:

1/8

Explanation:

[tex] \frac{1}{ {2}^{3} } = \frac{1}{8} [/tex]

Mark brainliest please

Answer:

see this

Explanation:

Answer:

D po

Explanation:

Sana nakatutulong

#Carry on learning

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Answer : The correct option is, Magnesium because it is a group 2 element with two valence electrons.

Explanation :

Element = Calcium

Atomic number = 20

Electronic configuration of Ca =  

Number of valence electrons in Ca = 2

The number of inner shell electrons in Ca = 18

This option is wrong because lewis-dot structure shows only valence electrons not inner shell electrons.

Element = Carbon

Atomic number = 6

Electronic configuration of C =  

Number of valence electrons in C = 4

This option is wrong because only outermost p-sublevel electrons are not showing in lewis-dot structure.

Element = Lithium

Atomic number = 3

Electronic configuration of Li =  

Number of valence electrons in Li = 1

This option is wrong because it has only 1 electron in outermost shell.

Element = Magnesium

Atomic number = 12

Electronic configuration of Ma =  

Number of valence electrons in Ma = 3

This option is correct.

Lewis-dot structure : It is defined as the structure in which valence electrons of the atom is shown as dots.

ANOTHER EXPLANATION:

Answer: C. Magnesium, because it is a group 2 element with two valence electrons.

An atom's Lewis dot structure has two dots. Which of the following elements could it be, and why?

A. Calcium, because it is an alkaline earth metal with two inner shell electrons.

B. Carbon, because it has two electrons in its outermost p sublevel.

C. Lithium, because it is a group 1 element with two bonding electrons.

D. Magnesium, because it is a group 2 element with two valence electrons.

Explanation:

If you were to look at the periodic table magnesium would be in group 2. Since magnesium is in group 2 therefore it will have two valence electrons. Calcium is another possible answer because it is also in group two, but for this quiz it is incorrect. Lithium is incorrect because it is in group 1 and therefore it would only have 1 valence electron. Carbon is also incorrect because it is in group 14 so it would have 4 valence electrons. Hope this helps and makes sense.

Good Luck!!

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The Lewis dot structure of an atom has three dots. With three valence electrons and belonging to group 13, which of the following elements may it be?

The semi-metal boron (B) and the metals aluminum (Al), gallium (Ga), indium (In), and thallium (In) are all members of the boron family (Tl). The periodic table's fifth element, boron (Z=5), is found in Group 13. It is categorized as a metalloid because of its characteristics, which combine those of metals and nonmetals.

The Periodic Table of Elements places these elements in Group 13 (XIII) of the p block. Metallic elements include thallium, gallium, indium, and aluminum. In their outermost shells, they each have three electrons shell with the valence electron configuration ns2np1 (one electron in the p orbital and a complete s orbital).

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.

Answer: 57.C

Explanation: simple subtraction

Answer:

Use calculator but first group them one by one and open the bracket by solving them accordingly

The number we get by this operation is 0.016. This number can be taken based on the rules for significant figures.

The number of significant figures is the number of digits that are known with certainty plus the last one having some uncertainty. All non zero values are significant and zero preceding first non zero digit is not significant .

For example in 65000, there are only two significant figures.  Similarly in 0.08 only one significant digit is present. Now when we multiply two decimal numbers, the result can only have as many decimal places as there are in the value with fewest decimal places.

First, multiply the numbers inside the bracket.  As per the above rule, the result should contain only two decimal places.

(0.08 ×200×0.004) = 0.06

Multiply by 65000 - 0.06×65000 = 3900

Now divide it by the multiplication product (800× 300), 240000 we get as follows:

3900÷240000 = 0.016

Hence the result of this operation is 0.016.

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Answer:

Element X has valency 2 while Y Valency 2, element Y has high tendency of gaining electrons for its stability thus the compound formed will be B

elements X is positively charged while Y will be negatively charged

The groups or the families in the periodic table are denoted by the vertical column. Element in group 2 and 7 forms compound with ions X²⁺ and Y⁻. Thus, option B is correct.

A group of the periodic table is also called a family that has the elements placed togther with the same number of the valence electron. Group II has two valence electrons and VII has seven valence electrons in the outer shells.

The two valence electrons of the atom can be donated easily compared to acquiring the six electrons to complete the octet and stability. Similarly, the seven valence electrons are hard to donate but can accept one electron to achieve satbility.

The group II element X will donate its two electrons to acquire a +2 charge, whereas group VII element Y will accept one electron and acquire a -1 charge.

Therefore, option B.  X²⁺ and Y⁻ presents the ions of the compound.

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Answer:

They all consist of the same amount of protons, electrons, and neutrons in an element.

Explanation:

For example in water (H20) contains 1 atom of protons, 1 atom of electrons and 1 atom of neutrons.

Answer:

The isooctane

Explanation:

A pure substance is, according to Wikipedia, "a chemical substance is a form of matter having constant chemical composition and characteristic properties." That's a lot of words, but we just need to focus on some of them: "constant... characteristic properties." The properties of a pure substance always stay the same, no matter what.

The boiling point of a substance is one of its properties. It looks like the petrol boils at different points, between 45 and 95°C. The isooctane, on the other hand, boils consistently at 99°C. So, we can infer that the isooctane is the pure substance.

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Answer:

Explanation:

Answer: Is it Conduction?

Explanation:

Answer:

The average kinetic energy increases, and the particles collide more frequently.

Explanation:

Answer:

Density 0.78945 g/cm3 (at 20 °C)

Melting point −114.14 ± 0.03 °C (−173.45 ± 0.05 °F; 159.01 ± 0.03 K)

Boiling point 78.23 ± 0.09 °C (172.81 ± 0.16 °F; 351.38 ± 0.09 K)

Solubility in water Miscible

Explanation:

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There is a golden role of solubility, polar solute dissolve in polar solvent and non polar solute dissolve in non polar solvent. Therefore, Salt and sand can be separated by dissolving the salt in water, filtering the mixture, and then evaporating the water to recover the salt.

Solutions are a homogeneous mixture of two or more substances. A solution is a homogeneous mixture of solvent and solute molecules. Solvent is a substance that is in large amount in solution.

Solute is the substance which is in small amount in a solution. Salt and sand can be separated by dissolving the salt in water, filtering the mixture, and then evaporating the water to recover the salt.

Therefore, Salt and sand can be separated by dissolving the salt in water, filtering the mixture, and then evaporating the water to recover the salt.

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