please begging you guys someone help me

Answer:

30 2 the second power

Explanation:

Calcium hydroxide, commonly known as hydrated lime or slaked lime, is a soft white powder that is used as a primary ingredient in the chemical industry.

Its chemical formula is Ca(OH)2. When calcium oxide and water are combined, it produces.

There are two hydroxide ions (OH) in the molecule for every calcium ion (Ca2+). The substance is ionic, and both electrolytic and aqueous dissociations result in calcium and hydroxide ions.

When water is added to dry portland cement to create concrete, this reaction takes place, and the mixture warms up and releases heat. An alternative method of manufacturing entails an aqueous double displacement reaction between sodium hydroxide and calcium chloride.

Therefore, Calcium hydroxide, commonly known as hydrated lime or slaked lime, is a soft white powder that is used as a primary ingredient in the chemical industry.

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Answer:

c

Explanation:

cuz

Answer:

A)

4, 7, 4, 6

B)

12 moles

Explanation:

[tex] NH_{3}(g) + O_{2}(g) \: → NO_{2} + H_{2}O(g)[/tex]

__↑______↑

8.00 mol | 14.00 mol

________________

[tex] NH_{3}(g) + O_{2}(g) \: → NO_{2} + H_{2}O(g)[/tex]

You can turn this into a system of variables which are solvable.

To do this, create variables for the coefficients of each compound in the reaction respectively.

[tex] a(NH_{3}(g)) + b(O_{2}(g)) → \\c(NO_{2}) + d(H_{2}O(g))[/tex]

Because to be balanced, the count of atoms in each element of the compound correspond to the coefficient of the variable in that compound so that the count of the left (reactant) side is set equal to the right (product) side.

a corresponds to the coefficient of the first compound, b corresponds to the coefficient of the second compound, c corresponds to the coefficient of the third compound, and d corresponds to the coefficient of the fourth compound.

(Reactant = Product)

Reactant: 1a [N] Product: 1c.

Reactant: 3a [H] Product: 2d.

Reactant: 2b [O] Product: 2c + 1d.

Thus the system is:

1a = 1c

3a = 2d

2b = 2c + 1d.

Then just use the substitution methods to solve.

Answer:

ily

Explanation:

When a wave moves through the air and comes into contact with an object, it hits its flat surface from a new angle, causing the wave to refract.

When waves cross the boundary between two different materials, their speed changes. For example, light waves refract when they pass through glass to air. Refraction is the effect that causes them to change direction as a result. When water waves move from deep water to shallow water (or the other way around), they refract light.

When waves bounce back from a surface they can't pass through, this is called reflection. When waves enter a new medium at an angle and begin traveling at a different speed, refraction occurs. Diffraction happens when waves spread out as they travel around impediments or through openings in obstructions.

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Answer:

1.2 × 10²¹ molecules

Explanation:

Step 1: Given data

Step 2: Calculate the number of moles corresponding to 0.045 L of nitrogen gas at STP

At STP, 1 mole of nitrogen gas occupies 22.4 L.

0.045 L × 1 mol/22.4 L = 2.0 × 10⁻³ mol

Step 3: Calculate the number of molecules in 2.0 × 10⁻³ moles of nitrogen

We will use Avogadro's number: there are 6.02 × 10²³ molecules in 1 mole of molecules of nitrogen gas.

2.0 × 10⁻³ mol × 6.02 × 10²³ molecules/1 mol = 1.2 × 10²¹ molecules

Answer:True

Explanation:

Answer: The solubility of this compound in pure water is 0.012 M

Explanation:

Solubility product is defined as the equilibrium constant in which a solid ionic compound is dissolved to produce its ions in solution. It is represented as [tex]K_{sp}[/tex]

The equation for the ionization of the  is given as:

[tex]Ca(OH)_2\rightarrow Ca^{2+}+2OH^-[/tex]  

By stoichiometry of the reaction:

1 mole of  [tex]Ca(OH)_2[/tex] gives 1 mole of [tex]Ca^{2+}[/tex] and 2 mole of [tex]OH^-[/tex]

When the solubility of  [tex]Ca(OH)_2[/tex] is S moles/liter, then the solubility of [tex]Ca^{2+}[/tex]  will be S moles\liter and solubility of [tex]OH^-[/tex] will be 2S moles/liter.

[tex]K_{sp}=[Ca^{2+}][OH^{-}]^2[/tex]

[tex]6.5\times 10^{-6}=[S][2S]^2[/tex]

[tex]S=0.012M[/tex]

Thus solubility of this compound in pure water is 0.012 M

Answer:

i have no clue

Explanation:

Answer:

1. It is stoichiometric.

2. O2 is the limiting reactant.

3. 9.0 g of C2H6 remain unreacted.

4. 17.6 g of CO2.

5. 85.2%.

Explanation:

Hello there!

In this case, for the given chemical reaction:

[tex]2C_2H_6+7O_2\rightarrow 4CO_2+6H_2O[/tex]

We can see that:

1. It is stoichiometric and is balanced because the reactants yields the products according to the law of conservation of mass.

2. In this part, it is possible to calculate the moles of ethane by using its molar mass:

[tex]n_{C_2H_6}=15g*\frac{1molC_2H_6}{30.08g} =0.50molC_2H_6[/tex]

And the moles of oxygen by knowing that one mole is contained in 22.4 L at STP:

[tex]n_{O_2}=\frac{1mol}{22.4L} *15.68L=0.7molO_2[/tex]

Thus, by calculating the moles of carbon dioxide product by each reactant, we can identify the limiting one:

[tex]n_{CO_2}^{by\ C_2H_6}=0.50molC_2H_6*\frac{4molCO_2}{2molC_2H_6} =1.0molCO_2\\\\n_{CO_2}^{by\ O_2}=0.70molO_2*\frac{4molCO_2}{7molO_2} =0.4molCO_2\\[/tex]

Thus, since oxygen yields the fewest moles of CO2 product, we infer it is the limiting reactant.

3. In this part, we calculate the mass of C2H6 that actually react first:

[tex]m_{C_2H_6}^{reacted}=0.4molCO_2*\frac{2molC_2H_6}{4molCO_2}*\frac{30.08gC_2H_6}{1molC_2H_6} =6.0gC_2H_6[/tex]

Thus, the leftover of ethane (C2H6) as the excess reactant is:

[tex]m_{C_2H_6 }^{leftover}=15g-6.0g=9.0g6.0C_2H_6[/tex]

4. Since 0.4 moles of carbon dioxide were produced, we use its molar mass to calculate the mass as its theoretical yield:

[tex]m_{O_2}^{theoretical}=0.4molCO_2*\frac{44gCO_2}{1molCO_2}=17.6gCO_2[/tex]

5. Finally, the percent yield is gotten by dividing the actual yield by the theoretical one:

[tex]Y=\frac{15g}{17.6}*100\%\\\\Y=85.2\%[/tex]

Best regards!

Answer:

solar energy drives the cycle by evaporating water from the oceans, lakes, rivers, and soil. As liquid water evaporates or transpires, it forms water vapor and clouds, where water droplets eventually gain enough mass to fall back to Earth as precipitation.

Answer True

Explanation:

Answer:

I would say the second one it's the wrong

Answer:

True

Explanation:

Because yes

Answer:

true because that is a reactant or the chemical

Explanation:

Answer:

B. Spring balance - a device used for measuring the weight or force of gravity acting on an object.

Explanation:

A Force is any interaction that changes the motion or position of an obkpjectbthatbit is interacting with. Whenever there is an interaction between two objects, there is a force exerted by each of the objects on one themselves.

Forces are generally divided into contact forces and non-contact over field forces.

In contact forces, the two objects physically in contact with each other. Examples of contact forces are push or pull forces, frictional forces, tensional forces, spring forces, etc.

Non-contact forces are forces in which the two objects interacting do no need to be physically in contact with one another. Examples include, gravitational forces, magnetic forces, electrical forces, etc.

Instruments used in measuring forces are known as force gauges.

From the instruments listed above:

A. A ruler is an instrument used in measuring length

B. Spring balance is a device used for measuring the weight or force of gravity acting on an object.

C. A thermometer is an instrument used in measuring temperature

D. A windbvane is an instrument used in measuring wind direction.

Answer:  it's part of the immune system that focuses on specific foreign particles. Rather than generically attack any antigens, T cells circulate until they encounter their specific antigen. As such, T cells play a critical part in immunity to foreign substances !

Explanation:

Answer:

a: they're used in saucepan handles 'cause they don't soften when heated and also 'cause they cant be bent easily.

b: thermosetting plastics are bad electricity conductors. they don't get moulded and are also hard and strong.

To prepare 267 mL of  0.25M NaCl, we need to take 38.29 mL of 1.75M NaCl solution and add water to it until it makes the final volume up to 267 mL.

We need to prepare the solution of 0.25 M NaCl using 1.75 M NaCl solution, we can use the dilution formula:

[tex]C_1V_1 = C_2V_2[/tex]

where [tex]C_1[/tex], [tex]V_1[/tex] is the concentration and the volume of the initial solution, [tex]C_2[/tex], [tex]V_2[/tex] is the concentration and the volume of the final solution.

We know the final concentration and the final volume that we are required to make. So we can use the above relation to find  [tex]V_1[/tex] of the solution:

[tex]V_1 = (C_2 * V_2) / C_1[/tex]

Now after substituting the values in the relation, we get:

[tex]V_1 = (0.25 M x 267 mL) / 1.75 M\\V_1 = 0.03829 L or 38.29 mL[/tex]

So to prepare 267 mL of  0.25M NaCl, we need to take 38.29 mL of 1.75M NaCl solution and add water to it until it makes the final volume up to 267 mL.

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Answer:

A. Alpha Particle

Explanation:

I think i could be wrong

Answer:

[tex] \frac{60}{28} = \frac{15}{7} [/tex]

Answer:

c i think

Explanation:

Answer:

Mg + 2HCl → MgCl2 + H2

Explanation:

Mg (s) + 2HCl (aq) → MgCl2 (aq) + H2

Answer:

Acid rain is caused by a chemical reaction that begins when compounds like sulfur dioxide and nitrogen oxides are released into the air. These substances can rise very high into the atmosphere, where they mix and react with water, oxygen, and other chemicals to form more acidic pollutants, known as acid rain.

Explanation:

Answer:

A half-reaction can be written to represent reduction. At the same time the magnesium atoms become ions, the oxygen atoms become –2 anions by gaining one electron each. By combining these two reactions, we have an oxidation reaction and a re- duction reaction, that are perfectly balanced.

Explanation:

Regroup terms.

2Mg+2O=2mgo

Subtract 2Mg2Mg from both sides.

2O=2mgo-2Mg

Factor out the common term 2.

2O=2(mgo-Mg)

Cancel 2 on both sides.

O=mgo−Mg

Answer:10,000 kg

Explanation:I went on my calculator and did 1,000 × 250 ÷ 25 or -25 to get 10,000 or -10,000 ;)

Answer:

The solution is nopolar

Explanation:

Answer:

The solution does NOT conduct electricity.

Explanation:

Nonelectrolytes are usually held together by covalent bonds rather than ionic ones.

Answer:

__1__CH4 + __2_O2→ __1__CO2 + _2__H2O

Answer:

The volume of the hydrogen produced is always twice the volume of the oxygen produced, because water contains two atoms of hydrogen for each atom of oxygen.