When magnesium chloride reacts with water, 5.85 L HCl(g) is produced.
molar mass of HCl = 36.5 g/mol
molar mass of MgCl2 = 95.2 g/mol

How many moles of HCl was produced?
How many moles of MgCl2 reacted?
What mass of MgCl2 reacted?

Answer:

Explanation:

Information given about the element:

Number of protons = 74

Number of neutrons = 110

For the atomic number:

Neutral atoms such as this one would have their atomic number to be the same with their number of electrons and protons:

     atomic number = number of protons = number of electrons

The atomic number would therefore be 74

For the mass number:

The mass of an atom is centrally concentrated within the tiny nucleus. The mass number is the sum of protons and neutrons in an atom. Protons and neutrons are nuclear particles and are called nucleons:

     Mass number = number of protons + number of neutrons = 74+110=184

Is this a new element?

From the peroidic table, tungsten(W) perfectly fits this description of the atom. It has an atomic number of 74 and a mass number of approximately 184. The element is not a new element.

Is it solid, liquid, or gas?

The element is a hard metallic solid. It is a classified as a transition metal on the periodic table. Transition metals have very unique metals and are mostly solids.

Answer:

1) The atomic number of this element is 74, because number of protons = atomic number

2) Mass number of this element is 184

Ar=Z+N=74+110=184

3) It isn't a new element. An element with such atomic and mass numbers exists

4) It is Wolfram. Symbol: W

5) Solid

Sorry if I made mistakes. I started learning English recently

Answer: The hydroxide ion concentration is [tex]1.26\times 10^{-4}M[/tex]

Explanation:

pOH is defined as the negative logarithm of hydroxide ion concentration in the solution.

To calculate the pOH of the reaction, we use the equation:

[tex]pOH=-\log[OH^-][/tex]

where,

[tex]pOH=3.90[/tex]

Putting values in above equation, we get:

[tex]3.90=-\log[OH^-][/tex]

[tex][OH^-]=1.26\times 10^{-4}M[/tex]

Hence, the hydroxide ion concentration is [tex]1.26\times 10^{-4}M[/tex]

Answer: 1.26 x 10 -4

Explanation:

Answer:

[tex]\boxed{11.13}[/tex]

Explanation:

The chemical equation is

[tex]\rm NH$_{3}$ + \text{H}$_{2}$O \, \rightleftharpoons \,$ NH$_{4}^{+}$ +\text{OH}$^{-}$[/tex]

For simplicity, let's rewrite this as

[tex]\rm B + H$_{2}$O \, \rightleftharpoons\,$ BH$^{+}$ + OH$^{-}$[/tex]

1. Initial concentration of NH₃

[tex]\text{[B]} = \dfrac{\text{moles}}{\text{litres}} = \dfrac{\text{0.050 mol}}{\text{0.500 L}} = \text{0.100 mol/L}[/tex]

2. Calculate [OH]⁻

We can use an ICE table to do the calculation.

                      B + H₂O ⇌ BH⁺ + OH⁻

I/mol·L⁻¹:     0.100              0         0

C/mol·L⁻¹:       -x                +x       +x

E/mol·L⁻¹:  0.100 - x           x         x

[tex]K_{\text{b}} = \dfrac{\text{[BH}^{+}]\text{[OH}^{-}]}{\text{[B]}} = 1.8 \times 10^{-5}\\\\\dfrac{x^{2}}{0.100 - x} = 1.8 \times 10^{-5}[/tex]

Check for negligibility:

\[tex]\dfrac{0.100 }{1.8 \times 10^{-5}} = 5600 > 400\\\\ x \ll 0.100[/tex]

3. Solve for x

[tex]\dfrac{x^{2}}{0.100} = 1.8 \times 10^{-5}\\\\x^{2} = 0.100 \times 1.8 \times 10^{-5}\\\\x^{2} = 1.80 \times 10^{-6}\\\\x = \sqrt{1.80 \times 10^{-6}}\\\\x = \text{[OH]}^{-} = 1.34 \times 10^{-3} \text{ mol/L}[/tex]

4. Calculate the pH

[tex]\text{pOH} = -\log \text{[OH}^{-}] = -\log(1.34 \times 10^{-3}) = 2.87\\\\\text{pH} = 14.00 - \text{pOH} = 14.00 - 2.87 = \mathbf{11.13}\\\\\text{The pH of the solution at equilibrium is } \boxed{\mathbf{11.13}}[/tex]

Answer:

These are the ten elements other than chromium and copper in the d-block don’t fit the expected configuration pattern:

niobium (Nb)

molybdenum (Mo)

ruthenium (Ru)

rhodium (Rh)

palladium (Pd)

silver (Ag)

platinum (Pt)

gold (Au)

darmstadtium (Ds)

roentgenium (Rg)

Explanation:

Answer:

ruthenium (Ru)

gold (Au)

silver (Ag)

Explanation:

Answer:

An atom becomes anion when it gains or loses electrons. The ions that are formed when an atom loses electrons are positively charged because they have more protons in the nucleus than electrons in the electron cloud.

Explanation:

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Answer: Sulfur atom will form a cation on loosing electrons.

Explanation:

There are 3 subatomic particles present in an atom. They are: protons, electrons and neutrons.

Protons carry positive charge, electrons carry negative charge and neutrons does not carry any charge.

Any neutral atom has equal number of protons and electrons.

An ion is formed when atom looses or gain electron.

If an atom gains electrons, it will have more number of electrons than protons. Thus, it will carry negative charge and form an anion.

If an atom looses electrons, it will have less number of electrons than protons. Thus, it will carry positive charge and forms a cation.

It is given that sulfur atom looses an electron. So, this atom will have more number of protons than electrons. Thus, it will form a cation.

Hence, sulfur atom will form a cation on loosing electrons.

Answer:

Resonance structures for the nitrate ion exist because there are more than one Lewis Structures for this ion.

Explanation:

How many bonds in each nitrate ion?

To answer this question, start by considering how many electrons each atom need for an octet.

The three O atoms and one N atom in each nitrate ion will need [tex]3\times 2 + 3 = 9[/tex] electrons in total to be stable. However, the ion carries a charge of [tex]-1[/tex]. In other words, atoms in the ion have already acquired one extra electron. Now they need only [tex]9 - 1 = 8[/tex] electrons.

Atoms share electrons by forming bonds. In effect, each chemical bond (a pair of shared electrons) adds two electrons to the bonding atoms. Atoms in the nitrate ion will form [tex]8/2 = 4[/tex] chemical bonds.

However, there are only three bonding position available. One of the three positions will see a double bond while each of the other two will see a single bond. However, the double bond can be at any of the three bonding position. There are thus three possible Lewis Structures. See the sketched. Note that the three structures are interconvertible by moving only the electrons but not any atoms. Hence the name resonance structures.

Keep in mind that in reality, the pi electrons from the double bond are delocalized across all three possible bonding positions. All three N-O bonds are of equal length.

The unknown solid with melting point of 78 degrees Celsius has been the molecular solid Naphthalene with formula [tex]\rm C_1_0H_8[/tex]. Thus, option A is correct.

Melting point has been defined as the temperature that has been able to transfer the solid to the liquid state.

The melting point has been higher for the substances with strong intermolecular interactions, and lower for weak attractive compounds.

The unknown sample has a melting point of 78 degree Celsius.

The molecular compounds have high melting point with strong intermolecular interactions, and ionic and covalent compounds have low melting point with weak intermolecular interactions.

The melting point of water has been zero degree Celsius.

Thus, the unknown solid with melting point of 78 degrees Celsius has been the molecular solid Naphthalene with formula [tex]\rm C_1_0H_8[/tex].

Thus, option A is correct.

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The most likely identity of the unknown white solid with a melting point of 78 °C is naphthalene, a molecular solid with the formula C10H8, commonly used in mothballs.

If the unknown substance is a white solid at room temperature and has a melting point of 78 °C, the most likely candidate from the given options would be naphthalene, which is a molecular solid. This substance has the formula C10H8 and is well-known for its use in mothballs. It has a melting point close to the given temperature, whereas the other given substances have significantly higher melting points and different chemical and physical properties.

SiO2, or silica, is a covalent network solid and CaCl2, or calcium chloride, is an ionic compound. Both have melting points that are much higher than 78 °C. Meanwhile, H2O, water, is a molecular compound that is not a solid at room temperature, as it has a melting point of 0 °C. Therefore, option A, naphthalene, is the most likely identity of the unknown solid.

As a temperature of a fixed volume of a gas increases, the

pressure will also “INCREASE”

Answer:

elta H = Potential Energy of the Products - Potential Energy of the Reactants.  

This would be C-A = delta H  

The activation energy would be B-A  

This is the energy necessary to start the reaction

Answer:

its the relationship between energies and the coeficcients on the graph.

Explanation:

Answer:

evaporates

Explanation:

the heat from the sun causes it to evaporate

Answer:

D. 1 × 10⁻⁴ m

Explanation:

Electromagnetic waves travel through space with the speed of light which is approximately 3.0 ×10⁻⁸ m/s.

The speed is calculated as follows:

c=λf

Where λ is the wavelength of the wave, f the frequency and c the speed of light.

Thus λ=c/f

=(3×10⁸ m/s) / (3×10¹²Hz)

Wavelength, λ= 1 × 10⁻⁴ m

Answer:

D

Explanation:

A.P.E.X.

Final answer:

Potassium nitrate (KNO3) contains both ionic and covalent bonds within the compound, while potassium sulfate (K2SO4) is an example of a compound containing only ionic bonds.

Explanation:

An example of a potassium compound containing both ionic and covalent bonds is potassium nitrate (KNO3), and an example containing only ionic bonds is potassium sulfate (K2SO4).

Potassium nitrate is composed of potassium ions (K+) and nitrate ions (NO3−), with the nitrate being a polyatomic ion held together by covalent bonds between nitrogen and oxygen atoms. This compound demonstrates ionic bonding between potassium and nitrate ions, as well as covalent bonding within the nitrate ion itself.

On the other hand, potassium sulfate is made up of potassium ions (K+) and sulfate ions (SO42−). This compound is purely ionic, with the bonds forming from the electrostatic attraction between the positively charged potassium ions and the negatively charged sulfate ions.

The scientific theory is "an idea that is backed by data from many sources".

A scientific theory would be a justification for a feature of the natural world as well as the universe that already has undergone repeated testing and confirmation through using established procedures for observation and measurement but also outcome from evaluation.

The source would be defined as the origin of somebody else.

Therefore, the scientific theory is "an idea that is backed by data from many sources".

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Answer:

restrict population growth ( second choice).

Answer:

Both apply to a certain region

Choice C is correct

Explanation:

Weather refers to the atmospheric conditions of a given place over a short period of time, like a day.

On the other hand, Climate refers to the average climatic conditions of a particular region measured over a long period of time.

Both weather and climate apply to a certain region.

Answer:

Yes; the graph shows a strong positive linear association.

Explanation:

Majority of the points outline a line of the graph. There are only a few outliers.

Answer:

1 Higher

2 High

3 High

4 Expands

Explanation:

Answer:

a) Water's boiling point is abnormally higher than expected

b) Water has a high surface tension allowing adhesion, cohesion and capillary action.

c) Water has a high capacity to retain heat, keeping moderate climates warmer in the winter.

d) Water expands as it freezes, so ice floats when expected to sink.

Explanation:

a) Because of its small molecular weight, it's expected that the water has a low boiling point, but the abillity to make hydrogen bonds generates an atraction force between the molecules much more stronger that expected.

This phenomenom implies that the water has higher boiling point than other heavier compounds.  

b) The high surface tension its the result of the hydrogen bonds and the polarity of the water molecules, giving the water molecules stronger bonds and like a very strong net, makes it harder to get through.

This is the cause of the listed phenomena: cohesion, adhesion and capillary action.

c) Another effect of the hydrogen bonds of the water is its high thermal capacity.

The hydrogen bonds are the strongest of the molecular bonds (H bonds, dipole-dipole and London) and the stronger the bond is, the higher the amount of energy (in this case heat) it can absorb before its rupture.

This is why water have a high thermal capacity compared with other molecules that only have London or dipole bonds.

d)  Water expands when it freezes because the molecules rearrange and during that, many of the hydrogen bonds break.

When that happens, the water molecules have a weaker attraction than before and in consecuence the water (ice) expands.

Also, ice floats beacuse once it expands it has a lower density compared to the water.

Answer:

3Ca + 2AlPO4 = Ca3(PO4)2 + 2Al.

That is B

Answer:

The stoichiometric coefficient of aluminium is 2 that is option B is correct.

Explanation:

Stoichiometric coefficient is the numeral coming or written before the symbol of compound or an element in balanced chemical reaction equation.

[tex]3Ca + 2AIPO_4 \rightarrow 2Al + Ca_3(PO_4)_2[/tex]

According to stoichiometry, 3 moles of calcium reacts with 2 moles of aluminum phosphate to give 2 moles of aluminium and 1 mole of calcium phosphate.

The stoichiometric coefficient of calcium is = 3

The stoichiometric coefficient of aluminum phosphate = 3

The stoichiometric coefficient of aluminium  = 2

The stoichiometric coefficient of calcium  phosphate  = 1

Answer: B) 4.2 M

Explanation:

Molarity = moles of solute/litre of solution

1560mL/1000 = 1.56 litres

6.5/1.56 = x/1

x = 4.2

M of solution = 4.2

Answer:

HCL being a strong electrolyte dissociates in water to give H+ and Cl- ions. KMnO4 being a strong oxidising agent oxidises Chloride ion(Cl-) to Cl2. ... Hence more amount of KMnO4 is usedup which results in error in reading. The situation is completely the opposite with K2Cr2O7.

hope this helps

Answer:

= 32.39 %

Explanation:

The relative atomic mass of sodium is 23, sulphur 32 while oxygen as a relative atomic mass of 16.

I mole of Na₂SO₄ has a relative mass of 2(23) + 32 + 4(16) = 142 grams

Of the value 142, the contribution of sodium is 2×23 =46

Thus the % composition is calculated:

46/142×100%= 32.39%  

Answer:

2. A piece of metal is placed in water and produces sparks and gas

Explanation:

The production of gas is usually a sign of a chemical reaction.  The metal is reacting with the water to form a new substance (the gas).

Incorrect answers and why:

1.  Changing colors can be a sign of a chemical reaction, but in this case it's more likely that the colors blended together.  (If it was something like two clear liquids combining to form a yellow liquid, then it would be more clear evidence of a chemical reaction)

3.  The liquid is boiling

4.  The powder dissolved into the liquid

I hope this helps!

The statement that is a sign a chemical reaction has occurred is a piece of metal is placed in water and produces sparks and gas. The correct option is b.

A chemical reaction is a process in which two or more substances called reactants react to form a different substance or compound, called a product. The metal reacts with water and forms gas and sparks in a chemical reaction.

Although a chemical reaction might cause colors to change, in this case, it's more likely that the hues just mixed. (If it involved the blending of two clear liquids to create a yellow liquid, that would be more convincing proof of a chemical reaction.)

Thus, the correct option is b. A piece of metal is placed in water and produces sparks and gas.

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Answer:

± 1 or ± 2

Explanation:

Electrovalent bonds are chemical bonds that are established on the premise of transferring electrons between two atoms.

In this bond type, a higly electronegative atom, typically a non-metal receives electrons from an atom with lesser electronegativity, a metal.

To know the number of electrons involved in forming electrovalent bonds, we typically look at the groups of atoms that combines to form the bond.

Metals are found in group I and II on the periodic table. Metals are electropositive and are good electron donors. These metals have 1 and 2 electrons in their valence shell respectively. In like manners, the more electronegative atoms are found in group VI and VII. The elements in these groups are non-metals with high electronegativity and requires just 1 and 2 electrons to complete their octet.

Answer:

± 1 or ± 2

Explanation:

Answer:

Because both the bonding electrons come from the oxygen atom.

Explanation:

A coordinate covalent bond is formed when both the bonding electrons are coming from the same atom.

Here in the given situation, when H+ forms a bond with the water molecule [tex] H _ 2 O [/tex] to form the hydronium ion [tex] H _ 3 O + [/tex], then it is referred to as a coordinate covalent bond since both the bonding electrons are coming from the oxygen atom.

Answer:

Both the shared electrons come from single atom

Explanation:

Coordinate covalent bond is a type of bond in which both the shared pair of electrons are come from single bond. Whereas in simple covalent bond, sharing electrons come from both the participant atoms.

Coordinate covalent bond is also called dative bond and the atom which share both the electrons are called donar atom.

For a coordinate covalent atom to from, one participant atom should have lone pair of electron and other atom should be deprived of electrons.

In [tex]H_2O[/tex] molecule, O atom has lone pair of electrons while H+ ions has deficiency of electrons, so O atom shares its lone pair of electrons with H+ ions which results in the formation of coordinate covalent bond and forms [tex]H_3O^+ molecules[/tex].

Answer:

1. scientist

2. society

3. We can communicate to people across the world in a fraction of a second, our grandparents would've had to pay an extra fee to call anyone outside of the country. We've also made progress in medicine, making diseases like cancer more treatable.

4. Passion, determination, and intelligence.

5. You could ask yourself what factors do the other trees have that the unhealthy tree not have and then create an experiment as to how the variable missing from the unhealthy tree affects plants.

6. Life science was affected by each of these branches.

7. Investigations take a long time because of observations, forming hypothesis, creating an experiment and analyzing the data and then revizing the experiment and the hypothesis. This can take years and cannot be limited to one year.

8. The contributions of these scientists are absolutely still valuable, without these contributions many of the things we know in the modern world wouldn't be known today. Such as the types of organelles and their functions, the periodic table, and the importance of oxygen for human beings.

Explanation:

Answer:

In general, a scientific law is the description of an observed phenomenon. It doesn't explain why the phenomenon exists or what causes it. The explanation of a phenomenon is called a scientific theory. It is a misconception that theories turn into laws with enough research.

Explanation:

Answer:

A scientific law is a description of an observed phenomenon.this is not an explanation of a phenomenon but a description.

Hypothesis becomes a law when  they follow a line of reasoning and formulate a theory.then once a theory has been evaluated through a series of testing it becomes a law.

Hope this helps and if it does pls mark as brainliest answer

Answer:

Saturated solution.

Explanation:

So, 10.0 g of KClO₃ forms a saturated solution.

When 10 g of KClO₃ are dissolved in 100 g of water at 30 degrees Celsius, a saturated solution is likely formed because the solubility of KClO₃ increases with temperature and is sufficient to dissolve this amount at 20 degrees Celsius.

The question is referring to the process of dissolving a chemical compound in water, which is a chemistry topic commonly studied in high school. When 10 g of KClO₃ (potassium chlorate) are dissolved in 100 g of water at 30℃, the type of solution that is formed depends on the solubility of KClO₃ at that temperature. Assuming the question implies 30 degrees Celsius, potassium chlorate has a solubility of about 7 g per 100 mL of water at 20℃. Since solubility generally increases with temperature, it's likely that the 10 g of KClO₃ will fully dissolve in 100 g of water at 30℃ to form a saturated solution. If all the solute dissolves, the solution is known as saturated; if the solute does not fully dissolve, any undissolved solute would result in a supersaturated solution if the excess was initially forced to dissolve under different conditions, or an unsaturated solution if there is still room for more solute to dissolve.

Answer:

simple salad

Explanation:

Hi.

Anwers : Vegetable salad.

Achievements.

Answer: A dominant gene.

Explanation:

Answer:

The dominant form of a gene

Explanation:

The capital letter, such as T, represents the dominant form of a gene in a punnett square.

Answer:

Acidic.

Explanation:

pH is a logarithmic function of [H+]:

pH = −log[H+]

pH is usually (but not always) between 0 and 14. Knowing the dependence of pH on [H+], we can summarize as follows:

If pH < 7, then the solution is acidic.

If pH = 7, then the solution is neutral.

If pH > 7, then the solution is basic.

Given pH is 6.75 so it is acidic.