Which statement describes how the binary ionic compound KBr is named?

Answer:54.82%

Explanation:

Percentage of carbon = mass of carbon in that compound/ mass of the compund *100

216/394*100 = 54.82%

Answer:

Q8) True

Q9) First ionization energy

Q10) Metal oxides

Explanation:

A common property of group one elements (alkali metals) is their combination with water to form basic solutions. E.g 2K(s)+2H2O(l)→2KOH(aq)+H2​(g).

The distance of the outermost electron in the atom from the nucleus is inversely related to the first ionization energy. As the distance between the outermost electron and the nucleus in group 17 elements gets larger, the corresponding first ionization energies of elements in the group gets smaller.

Group 1 elements can combine with oxygen to give metal oxides. E.g  4K + O2 --> 2 K2O

Answer:

b its radiant energy that heats up the earth.

Explanation:

Answer:

The answer is D

Explanation:

Heat from the Earth's core and radiation from the Sun is transferred to the surface of the Earth by conduction. The warm land and water radiates infrared, some of which is absorbed by the atmosphere, adding to its thermal energy.

Answer: Magnesium

Magnesium, in its elemental form, has 12 protons and 12 electrons. The neutrons are a different matter. Magesium's average atomic mass is 24.305 atomic mass units, but no magnesium atom has exactly this mass.

Hope this helps....... Stay safe and have a Merry Christmas!!!!!!!! :D

Answer:

Thermal energy

Explanation:

When gasoline, coal, batteries and logs are all burn they transform chemical energy to thermal energy.

The chemical energy is the energy held between chemical chains and bonds within an atom.

Answer:

A and B

Explanation:

Trust me I just did it on a p e x

Answer: he’s correct it’s d and b for me but it’s the same answers

Explanation:

Answer:

90.4 mL

Explanation:

Step 1: Given data

Step 2: Calculate the final volume of the gas

According to Boyle's law, the volume of a gas is inversely proportional to the pressure. We can calculate the final volume of the gas using the following expression.

P₁ × V₁ = P₂ × V₂

V₂ = P₁ × V₁ / P₂

V₂ = 721 mmHg × 113 mL / 901 mmHg

V₂ = 90.4 mL

Answer:

They need more oxhygen to fraction to incresse

Explanation:

Answer:

69.09 g

Explanation:

First we calculate the mass of the sample of concentrated H₂SO₄, using the given volume and density:

There are 70.288 grams of solution, of which 98.3% is H₂SO₄. Thus the H₂SO₄ mass is:

Taking into account the definition of density and percentage by mass, the mass of H₂SO₄ in a 38.2 cm³ sample of concentrated sulfuric acid is 69.09 grams.

But first you must know the definition of density. Density is defined as the property that matter, whether solid, liquid or gas, has to compress into a given space.

In other words, density is a quantity that allows us to measure the amount of mass in a certain volume of a substance. Then, the expression for the calculation of density is the quotient between the mass of a body and the volume it occupies:

[tex]density=\frac{mass}{volume}[/tex]

In this case, you know that:

Density= 1.84 [tex]\frac{g}{cm^{3} }[/tex]

Volume= 38.2 cm³

Replacing in the definition of density:

[tex]1.84 \frac{g}{cm^{3} }=\frac{mass}{38.2 cm^{3} }[/tex]

Solving:

mass= 1.84 [tex]\frac{g}{cm^{3} }[/tex]×38.2 cm³

mass= 70.288 g

So, the mass of the solution is 70.288 grams.

The percentage by mass expresses the concentration and indicates the amount of mass of solute present in 100 grams of solution.

In other words, the percentage by mass of a component of the solution is defined as the ratio of the mass of the solute to the mass of the solution, expressed as a percentage.

The percentage by mass is calculated as the mass of the solute divided by the mass of the solution, the result of which is multiplied by 100 to give a percentage. This is:

[tex]percentage by mass=\frac{mass of solute}{mass of solution}x100[/tex]

In this case, you know:

percentage by mass=98.3%

mass of solute= ?

mass of solution= 70.288 grams

Replacing in the definition of percentage by mass:

[tex]98.3=\frac{mass of solute}{70.288 grams}x100[/tex]

Solving:

[tex]\frac{98.3}{100} =\frac{mass of solute}{70.288 grams}[/tex]

[tex]0.983=\frac{mass of solute}{70.288 grams}[/tex]

0.983× 70.288 grams= mass of solute

69.09 grams= mass of solute

The mass of H₂SO₄ in a 38.2 cm³ sample of concentrated sulfuric acid is 69.09 grams.

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density:

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percentage by mass:

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Answer:

Explanation:

The mass of the football can be found by using the formula

[tex]m = \frac{f}{a} \\ [/tex]

f is the force

a is the acceleration

From the question we have

[tex]m = \frac{600}{30} = \frac{60}{3} \\ [/tex]

We have the final answer as

Hope this helps you

Answer:

The correct answer is 70.41 kJ ≅ 70.4 kJ

Explanation:

The heat required to sublimate the solid at its sublimation temperature is calculated by using the following formula:

heat = ΔHs x moles of substance

Where ΔHs is the heat of sublimation, which is known (32.3 kJ/mol).

So, we have to calculate the moles of substance. For this, we can divide the mass of substance by the molecular weight of substance (CO₂):

mass CO₂ = 96.0 g

molecular weight CO₂ = (12 g/mol x 1) + (16 g/mol x 2) = 44 g/mol

⇒ moles of CO₂ = mass CO₂/molecular weight CO₂ = (96.0 g)/(44 g/mol) = 2.18 moles

Finally, we use the first formula to calculate the heat:

heat = ΔHs x moles = 32.3 kJ/mol x 2.18 mol = 70.41 kJ ≅ 70.4 kJ

Answer:

d) none of the above

Explanation:

The law that describes the relationship between pressure and volume of an ideal gas (under constant temperature and amount of substance) is Boyle's law.

It states that pressure is inversely proportional to the volume. This would mean that a graph of P vs 1/V would be a line.

See the attached picture for a graph of P vs V.

A plot of pressure VS. volume for an ideal gas will result in d) none of the above

The following things should be considered:

Therefore we can conclude that a plot of pressure VS. volume for an ideal gas will result in d) none of the above

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Answer:

The picture represents oxygen.

Explanation:

There are two notable ways you can figure this out:

1) Since there are eight protons, you can automatically know that you are looking for an element with an atomic number of 8. This is because the atomic number is the number of protons in an atom.

2) You can also note the number of electrons on the outer shell. These are called valence electrons. You can then see that the element has 6 valence electrons. Beginning with Lithium on the periodic table and count by ones going from left to right in period 2 of the periodic table until you get to 6. What element is that? It is indeed oxygen.

Answer:

Oxygen

Explanation:

Neons contain 8 protons and 10 ELECTRONS

Boron contains 5 protons an 5 electrons

calcium contains 20 electrons an 0 protons

Answer:

D. 2 NO3(aq)+Ca2+

Explanation:

Reaction of calcium nitrate and potassium phosphate produce calcium phosphate and potassium nitrate. The net ionic equation for this is written as : [tex]3 Ca^{2+} (aq) +2PO_{4} ^{3-} (aq) \rightarrow Ca_{3}(PO_{4} )_{2} (s)[/tex]. Thus option C is correct.

What is double displacement reaction?

In a double displacement reaction, two species or groups in reactant side are displaced in the products.

In a balanced chemical equation, all the reactants have to be in proper stochiometric ratio and the states of all species are mentioned in brackets.

In an ionic equation all the ions and charges are balanced both side and the number of each elements on both side too. The net ionic equation represents the formation of a solid product from its ions.

The balanced molecular equation and complete ionic equation are written for the given  reaction below:

[tex]3 Ca (NO_{3})_{2} (aq)+ 2K_{3} PO_{4} (aq) \rightarrow Ca_{3}(PO_{4} )_{2} (s) + 6 KNO_{3}(aq)[/tex]

[tex]3 Ca^{2+} (aq) +6 NO_{3}^{-} + (aq)+ 6K^{+} + (aq) 2PO_{4} ^{3-} (aq) \rightarrow Ca_{3}(PO_{4} )_{2} (s) + 6 NO_{3}^{-} (aq)+ 6K^{+} (aq)[/tex]

Now when the same species on both side is cancelled, then the net ionic equation is written as:

[tex]3 Ca^{2+} (aq) +2PO_{4} ^{3-} (aq) \rightarrow Ca_{3}(PO_{4} )_{2} (s)[/tex]

Therefore, the correct et ionic equation is option c.

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Answer:

[tex]Zn(s)+2H^+(aq)\rightarrow Zn^{2+}(aq)+H_2(g)[/tex]

Explanation:

Hello!

In this case, since writing the net ionic equation implies the complete molecular equation, we should start by:

[tex]Zn(s)+2HBr(aq)\rightarrow ZnBr_2(aq)+H_2(g)[/tex]

Next, we represent the ionization of the aqueous species:

[tex]Zn(s)+2H^+(aq)+2Br^-(aq)\rightarrow Zn^{2+}(aq)+2Br^-(aq)+H_2(g)[/tex]

Whereas the spectator ions, those at both reactants and products are cancelled out so the net ionic equation is obtained:

[tex]Zn(s)+2H^+(aq)\rightarrow Zn^{2+}(aq)+H_2(g)[/tex]

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Answer:

Cesium (Cs)

Explanation:

This eliment has an ionization energy of 3,8939

1. 0.33 M

2. 0.278 M

Molarity is a way to express the concentration of the solution

Molarity shows the number of moles of solute in every 1 liter of solute or mmol in each ml of solution

[tex]\large{\boxed {\bold {M ~ = ~ \frac {n} {V}}}[/tex]

Where

M = Molarity

n = Number of moles of solute

V = Volume of solution

1. 0.350 mol of NaOH in 1.05 L of solution.

n=0.35

V=1.05 L

Molarity :

[tex]\tt M=\dfrac{0.35}{1.05}=0.33[/tex]

2. 14.3 g of NaCl in 879 mL of solution.

mol NaCl(MW=58.5 g/mol) :

[tex]\tt mol=\dfrac{mass}{MW}\\\\mol=\dfrac{14.3~g}{58.5~g/mol}=0.244[/tex]

Molarity :

[tex]\tt M=\dfrac{0.244}{0.879~L}\\\\M=0.278[/tex]

Answer:

a) 2.01 g

Explanation:

First we convert 0.0302 mol AgNO₃ to Na₂CO₃ moles, in order to calculate how many Na₂CO₃ moles reacted:

So the remaining Na₂CO₃ moles are:

Finally we convert Na₂CO₃ moles into grams, using its molar mass:

The closest answer is option a).

Answer:

A. When a piece of copper is heated, it combines with oxygen to form copper oxide. The chemical reaction for the same is as follows:

              2 Cu (s) + O2(g) => 2CuO

B. The mass of the piece of copper will remain same and there will be no change in its mass. However, its volume will increase, so its density will decrease.

C. This is so because heating copper in its elemental form is a physical change and there is no change in mass during a physical change. Hence, the mass of copper remain same.

Answer:

You can not make the observation in the lab

Explanation:

We must know the amount of Nitrogen-16 that remains after 57 seconds before we can make our conclusion.

Hence, from;

N/No = (1/2)^t/t1/2

Where;

N = amount of Nitrogen-16 present after 57 seconds

No = 100g of Nitrogen-16 originally present

t = 57 seconds

t1/2 = half life of Nitrogen-16 which is 7.13 seconds

Substituting values;

N/100 = (1/2)57/7.13

N/ 100 =(1/2)^8

N/100 = 1/256

256N = 100

N = 100/256

N = 0.39 g

You can not make the observation because you need at least 5g of Nitrogen-16 and only 0.39 g is left after 57 seconds.

The minimum amount of sample required has been 5 grams, while the remaining sample has been 0.39 grams. Thus, it has not been possible to make the observations.

The half life can be defined as the time required for the sample to reduce to half of its initial concentration. The half life can be given as:

Amount remained = Initial amount [tex]\rm \times\;\dfrac{1}{2}^\dfrac{time}{Half-life}[/tex]

The half life of nitrogen 16 has been 7.13 second.

The initial concentration of the sample has been 100 grams.

The concentration of sample remained after 57 seconds has been:

Amount remained = 100 [tex]\rm \times\;\dfrac{1}{2}^\dfrac{57\;sec}{7.13\;sec}[/tex]

Amount remained = 0.39 grams.

The amount of sample remained after 57 seconds has been 0.39 grams.

The amount of sample required for the analysis has been 5 grams, after 57 seconds only 0.39 grams of sample has been remaining. Thus, the student will not be able to made analysis of nitrogen-16.

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Answer:

C

Explanation:

I hope that helps!!! it kinda gave you the answer though

Answer:

H=mc∆T

H=15×4.18×20

H=1254J

Answer:

76.1%

Explanation:

The reaction that takes place is:

First we determine how many moles of each reactant were added:

Thus K₂SO₄ is the limiting reactant.

Using the moles of the limiting reactant we calculate how many moles of BaSO₄ would have been produced if the % yield was 100%:

Then we convert that theoretical amount into grams, using the molar mass of BaSO₄:

Finally we calculate the % yield:

Answer:

No because a straw is plastic look at it by this was, the energy used to create one metal straw is roughly equivalent to creating 90 plastic straws, and also produces carbon emissions equivalent to 150 plastic straws. This may not seem like a lot, but in order to offset the environmental impact of creating a metal straw, it must be used over 150 times

Explanation:

Answer: D) 1.30 and 2.60

Explanation:

Molarity of a solution is defined as the number of moles of solute dissolved per liter of the solution.

[tex]Molarity=\frac{n\times 1000}{V_s}[/tex]

where,

n = moles of solute

[tex]V_s[/tex] = volume of solution in ml

molarity  of [tex]MgCl_2[/tex] = [tex]\frac{0.325\times 1000}{250ml}=1.30 M[/tex]

[tex]MgCl_2\rightarrow Mg^{2+}+Cl^{-}[/tex]

As 1 mole of [tex]MgCl_2[/tex] dissociates to give one mole of [tex]Mg^{2+}[/tex] and two moles of  [tex]Cl^-[/tex] ions .

Molarity of [tex]Mg^{2+}[/tex] = 1.30 M

Molarity of [tex]Cl^{-}[/tex] = [tex]1.3 M\times 2=2.60M[/tex]