Calculate the density (in g/mL) of an object that has a mass of 3.81 g and a volume of
14.3 mL.

Answer:

Q8) True

Q9) First ionization energy

Q10) A metal oxide

Explanation:

One of the properties of group one elements (alkali metals) is that they combine with water to form basic solutions. E.g 2Na(s)+2H2O(l)→2NaOH(aq)+H2​(g).

An inverse relationship exists between the distance of the outermost electron in the atom from the nucleus and the first ionization energy. As the distance between the outermost electron and the nucleus in group 17 elements increases, their first ionization energies decreases accordingly.

Group 1 elements react with oxygen to yield the corresponding metal oxides. E.g  4 Na + O2 --> 2 Na2O

Answer:

Ion exchange.

Explanation:

One of the ways in which water can be treated is through the process known as ION EXCHANGE. Using this for treating water has to do basically with the transfer or say the exchange of ions.

Ion exchanges is done by exchanging ions which are considered as 'unfit' or contaminants by the ones that are "fit".

Ions from what is known as zeolite or resin is been exchanged with the ions in the water. Cations are exchanged with cations and anions are exchanged with anions.

NB: this method is a good method or removing contaminants that are ions but not contaminants that are not ions.

Answer:

A chemical change has occurred

Explanation:

Given reaction expression:

      CaCO₃ →  CaO  +  CO₂

The reaction is a decomposition reaction in which a compound is dissociated into simple products.

The reason why the products have different properties than the reactants is because a chemical change has occurred.

The products of the decomposition of calcium carbonate have different properties because a chemical change has occured in the reaction to form new substances.

Learn more about chemical change at: https://brainly.com/question/1161517?referrer=searchResults

Answer:

because cycle is a prosess that goes through multiple stages

Explanation:

.

The concentration of OH⁻ ions will become 10 times the initial concentration.

A more useful approach to express the concentration of hydrogen ions is on the pH scale, which is the logarithm of the reciprocal of the hydrogen ion concentration in gram moles per liter. The concentrations of the hydrogen ion (H+) and the hydroxyl ion (OH) are both equal to 10⁻⁷ in a neutral solution. The pH of seven is neutral.

Solution pH 1 equals 8.

Solution's pH is 2 = 9.

pOH₁ = 14 - 8 = 6

pOH₂ = 14 - 9 = 5

OH₁⁻ = 10⁻⁶

OH₂⁻ = 10⁻⁵

Ratio = 10⁻⁵ / 10⁻⁶ = 10

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The final temperature of the mixture : 21.1° C  

The law of conservation of energy can be applied to heat changes, i.e. the heat received / absorbed is the same as the heat released  

Q in(gained) = Q out(lost)  

Heat can be calculated using the formula:  

Q = mc∆T  

Q = heat, J  

m = mass, g  

c = specific heat, joules / g ° C  

∆T = temperature difference, ° C / K  

Q ethanol=Q water

mass ethanol=

[tex]\tt mass=\rho\times V\\\\mass=0.789\times 45=35.505~g[/tex]

mass water =

[tex]\tt mass=1~g/ml\times 45~ml=45~g[/tex]

then the heat transfer :

[tex]\tt 35.505\times 2.42~J/g^oC\times (t-6)=45\times 4.18~J/g^oC\times (28-t)\\\\85.922t-515.533=5266.8-188.1t\\\\274.022t=5782.33\rightarrow t=21.1^oC[/tex]

Answer:

Yes

Explanation:

A krypton atom will remain the same despite changing the number of neutrons they contain.

The neutron is a nuclear particle found within an atom.

Answer: Hello! I do believe the answer is A.

Explanation: please mark me brainliest! hope this helps

Answer:

B

Explanation:

Answer:

Ultraviolet

Explanation:

It doesn't use much energy and so it creates ultraviolet light.

The percent yield : 4. 84.58%

Reaction

CaCO₃ ⇄ CaO+CO₂

mass CaCO₃ = 2.3 × 10³ g

mol CaCO₃ (MW=100.0869 g/mol) :

[tex]\tt mol=\dfrac{mass}{MW}\\\\mol=\dfrac{2.3\times 10^3}{100,0869}\\\\mol=22.98[/tex]

From the equation, mol CaCO₃ : CaO = 1 : 1, so mol CaO=22.98

mass CaO(MW=56.0774 g/mol)⇒ (theoretical) :

[tex]\tt mass=mol\times MW\\\\mass=22.98\times 56,0774\\\\mass=1288.659~g[/tex]

The percent yield :

[tex]\tt \%yield=\dfrac{actual}{theoretical}\times 100\%\\\\\%yield=\dfrac{1090}{1288.659}\times 100\%\\\\\5yield=84.58\%[/tex]

Answer:

please follow me

Explanation:

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Answer:

answer is d

Explanation:

because it is surrounded by water

Answer:

When balancing redox reactions under acidic conditions in aqueous solution, oxygen is balanced by adding water as much as oxygen we have, on the opposite side, where the oxygens are.

Explanation:

We can see this redox balance, in order to determine what we said.

The unbalanced reaction is: MnO₂  +  HCl  →  MnCl₂ + Cl₂ + H₂O

The HCl determines, we are in acidic conditions.

We need to determine the half reactions:

Mn⁴⁺  →  Mn²⁺  (In this case, the oxidation number decreased)

This is the reduction. Mn caught 2 electrons

Mn⁴⁺  + 2e⁻  →  Mn²⁺

Cl⁻ → Cl₂

In ground state, the oxidation number is 0. The chloride was oxidized to chlorine. As Cl is a dyatomic molecule, we need 2 chlorides to balance so finally it released 2 electrons. This is the oxidation (ox. number has increased) 2Cl⁻ → Cl₂ + 2e⁻

Mn⁴⁺  + 2e⁻  →  Mn²⁺

2Cl⁻ → Cl₂ + 2e⁻

Mn⁴⁺  + 2Cl⁻ →  Mn²⁺ + Cl₂

Now we balance the oxygen. In reactant side, we have 2, so we complete with 2 water in the product side. We add water as much as oxygen we have, on the opposite side, where the oxygens are. (If we have 2 oxygen in reactant side, and we have 1 water, we need 1 more water)

So, as we added 2 H₂O, we complete with protons, on the opposite side

Mn⁴⁺  + 4H⁺  + 4Cl⁻ →  Mn²⁺ + 2Cl⁻ + Cl₂ + 2H₂O

(Notice, we had 2Cl⁻, but globally we have 4H⁺. At least, we have 4HCl)

The balanced equation is: MnO₂  + 4HCl →  MnCl₂ + Cl₂ + 2H₂O

Answer:

C)a mass number of 38

Explanation:

yes

Answer:

There are 58 people in the cinema.

Explanation:

This number is actually exact and not subject to sig, digit rules.

Answer:

opp

Explanation:

Explanation:

Typically, only one element is present, so all atomic radii are the same. -Metallic bonding is not directional. -Nearest neighbor distances tend to be small in order to lower bond energy.

Answer:

Explanation:

Sodium and Iodine are in columns 2 and 17. They will be ionic.

Copper and oxygen will be ionic. Oxygen is a powerful receiver of electrons.

Magnesium and Chlorine same answer as the first one.

Carbon and Sulfur. Not so much. They do not form an ionic bond. They are basically closer to being two non metals.

Answer:

just multiply 18.6 to molar mass of cuso4.5h20

Explanation:

if you have any doubt comment

Answer:

It's because the NaCl and MgCl2 is shorter and easier to remember

The mass of Ba(CIO₃)₂ : 121.72 g

Reaction

Ba(OH)₂ + 2HCIO₃ ----> Ba(CIO₃)₂ + 2H₂O

Limiting reactant :

Ba(OH)₂ : 2HCIO₃ =

mol Ba(CIO₃)₂ based on limiting reactant(HCIO₃) :

[tex]\tt \dfrac{1}{2}\times 0.8=0.4[/tex]

MW Ba(CIO₃)₂ =Ba+2.Cl+6.O=137.3 + 2 x 35.5 + 6 x 16 = 304.3

mass of Ba(CIO₃)₂ :

[tex]\tt mass=mol\times MW\\\\mass=0.4\times 304.3=121.72~g[/tex]

Answer:

234.213

Explanation:

Moles of Nickel x 58.70 = Grams

3.99 x 58.70 = 234.213

Answer:

The correct answer is HOF gas.

Explanation:

Based on the given information, the helium atoms effuses three times faster in comparison to the gas X.

The rate of effusion is determined by,

r is inversely proportional to 1/√M, here M is the molecular mass of the gas.

and r is inversely proportional to 1/t, here t is the time taken for effusion.

Thus, t is directly proportional to √M

The molecular mass of He is 4.

tHe = tX/3 (Here tx is the time taken for gas X)

The molecular mass of X is not known.

tX/tHe =√Mx/MHe

3 = √Mx/4

By squaring both the sides we get,

9 = Mx/4

Mx = 36

36 is the molecular mass of gas HOF, that is, (1+16+19 = 36). Hence, the gas X is 36.

Answer:

0.954

Explanation:

1000 grams is 1 kg

954 grams is 954/1000 kg or 0.954

Moles H₂ needed = 52.2

A reaction coefficient is a number in the chemical formula of a substance involved in the reaction equation. The reaction coefficient is useful for equalizing reagents and products.

Reaction

N₂(g)+3H₂(g)⇒2NH₃(g)

From the reaction equation above, the reaction coefficient shows the mole ratio of reagents and products

moles NH₃ produced = 34.8

mol H₂: moles NH₃ = 3: 2, so moles H₂ :  

[tex]\tt moles~H_2=\dfrac{coefficient~H_2}{coefficient~NH_3}\times moles~NH_3\\\\moles~H_2= \dfrac{3}{2}\times 34.8=52.2[/tex]