_____ waves are the p and s waves of an earthquake that shake the rocks beneath the surface as they travel along

svet-max [94.6K]

Answer:

The correct answer is - D. the energy stored inside the center of an atom.

Explanation:

Each atom has a small center in it called the nucleus and the energy that holds the nucleus or center of the atom together in the atom is known as nuclear energy.

It is the energy that is stored in the center of the atom and normally does not come out, however, in some radioactive atoms the sends some part of the energy as radiation.

Thus, the correct answer is - D. the energy stored inside the center of an atom.

6 0

3 years ago

From the enthalpies of reaction H2(g)+F2(g)→2HF(g)ΔH=−537kJ C(s)+2F2(g)→CF4(g)ΔH=−680kJ 2C(s)+2H2(g)→C2H4(g)ΔH=+52.3kJ calculate

DIA [1.3K]

Answer:

$\Delta H$ for the given reaction is -2486.3 kJ

Explanation:

The given equation can be written as a combination of the following equation:

$2H_{2}(g)+2F_{2}(g)\rightarrow 4HF(g)$ ; $\Delta H_{1}= (2\times -537kJ)=-1074 kJ$

$2C(s)+4F_{2}(g)\rightarrow 2CF_{4}(g)$ ; $\Delta H_{2}=(2\times -680kJ)=-1360kJ$

$C_{2}H_{4}(g)\rightarrow 2C(s)+2H_{2}(g)$ ; $\Delta H_{3}=-52.3kJ$

-----------------------------------------------------------------------------------

$C_{2}H_{4}(g)+6F_{2}(g)\rightarrow 2CF_{4}(g)+4HF(g)$

$\Delta H=\Delta H_{1}+\Delta H_{2}+\Delta H_{3}=(-1074-1360-52.3)kJ=-2486.3kJ$

6 0

3 years ago

Write briefly on carbohydrates

Darya [45]

Answer:

carbohydrates are simple sugars which can be broken down to form 3 sugars.

which are , (maltose) (fructose) & (glucose)

6 0

3 years ago

g . Calculate the molar concentration for each of the following solutions. (a) 1.50 g NaCl in 100.0 mL of solution (b) 1.50 g K2

oksano4ka [1.4K]

Answer:

(a) $M=0.257M$

(b) $M=0.0510M$

(c) $M =0.500M$

(d) $M= 0.391M$

Explanation:

Hello,

In this case, since the molarity or molar concentration of a solution is computed by dividing the moles of solute by the volume of solution in liters, we proceed as follows:

(a) The molar mass of sodium chloride is 58.45 g/mol and the volume in liters is 0.100 L, therefore, the molarity is:

$M=\frac{1.50gNaCl}{0.100L} *\frac{1molNaCl}{58.45gNaCl} =0.257M$

(b) The molar of potassium dichromate is 294.2 g/mol and the volume in liters is 0.100 L, therefore, the molarity is:

$M=\frac{1.50gK_2Cr_2O_7}{0.100L} *\frac{1molK_2Cr_2O_7}{294.2gK_2Cr_2O_7} =0.0510M$

(c) The molar of calcium chloride is 111 g/mol and the volume in liters is 0.125 L, therefore, the molarity is:

$M=\frac{5.55gCaCl_2}{0.100L} *\frac{1molCaCl_2}{111gCaCl_2} =0.500M$

(d) The molar of sodium sulfate is 142 g/mol and the volume in liters is 0.125 L, therefore, the molarity is:

$M=\frac{5.55gNa_2SO_4}{0.100L} *\frac{1molNa_2SO_4}{142gNa_2SO_4} = 0.391M$

Best regards.

4 0

3 years ago

Give the mass percent of nitrogen in C14H19NO2.

leonid [27]

Answer:

The mass percent of carbon in C₁₄H₁₉NO₂ is 72.1%.

Explanation:

To calculate the mass percent of carbon in C₁₄H₁₉NO₂ we have to follow two simple steps:

1st) Look for the atomic weight of each element in the Periodic Table and then multiply each one by its subscript in the molecule and finally sum all of them to find the molar weight of the molecule:

Carbon atomic weight . Carbon subscript = 12 . 14 = 168g

Hydrogen atomic weight . Hydrogen subscript = 1 . 19 = 19g

Nitrogen atomic weight . Nitrogen subscript = 14 . 1 = 14g

Oxygen atomic weight . Oxygen subscript = 16 . 2 = 32g

The molar weight of C₁₄H₁₉NO₂ is: 168g + 19g + 14g +32g = 233g.

2nd) Find the mass percent of carbon with a Rule of three:

If 233g represents the 100% of mass, the 168g of carbon in the molecule will represents the 72.1% of mass.

The Rule of three is:

233g ------------- 100%

168g ------------- = (168 . 100)/233 = 72.1% mass of carbon.

5 0

2 years ago