How many grams are in 3.78 x 10^22 molecules of SO2?

If the neutral atom of an element has only 4 valence electrons it must be in which group? 1. IVB 2. VA 3. VIIA 4. VIA 5. IVA 6.

lisabon 2012 [21]

Answer:option

Option 5..IVA

Explanation:

5 0

3 years ago

Which of the following is unchanged at the end of the CNO cycle?

Musya8 [376]

Answer:

The correct option is: A. carbon-12

Explanation:

The CNO cycle, the abbreviation for the carbon-nitrogen-oxygen cycle, is a catalytic cycle by which the stars produce helium from elemental hydrogen, via a series of nuclear fusion reactions.

This cycle involves the fusion of four protons with carbon ( $_{6}^{12}\textrm{C}$ ), nitrogen isotope ( $_{7}^{13}\textrm{N}$ ), and oxygen isotope ( $_{8}^{15}\textrm{O}$ ), to give an alpha particle and two electron neutrinos and positrons.

The reaction involves the regeneration of carbon ( $_{6}^{12}\textrm{C}$ ) nucleus in the last step.

$_{6}^{12}\textrm{C}$ → $_{7}^{13}\textrm{N}$ → $_{6}^{13}\textrm{C}$ → $_{7}^{14}\textrm{N}$ → $_{8}^{15}\textrm{O}$ → $_{7}^{15}\textrm{N}$ → $_{6}^{12}\textrm{C}$

3 0

3 years ago

When an alkaline earth metal, a, reacts with a halogen, x, the formula of the covalent compund formed should be a2x?

Ierofanga [76]

Alkaline earth metal are the elements present in II group in the periodic table and are known as 'Metals' and have a charge of +2.

Alkaline earth metals - Be , Mg Ca, Sr , Ba, Ra

Halogens are present in VII A group in the periodic table and are 'Non-metals' and have a charge of -1.

Halogens - F, Cl, Br, I, At

When Alkaline earth metal (metals) combine with Halogens (non-metals) the compound formed will be ionic compound and the formula of the compound will be based on the charges of the element.

When we write the formula of the ionic compound the charges of the elements get criss crossed.

For example - Mg (Alkaline earth metal) have a charge of +2 and Cl (Halogen) have a charge of -1 and when they combine to form the formula their charges get criss crossed and we will get $Mg_{1}Cl_{2}$ or $MgCl_{2}$

When an alkaline earth metal, A, reacts with a halogen, X, the formula of the Ionic compound formed should be $AX_{2}$

3 0

3 years ago

Explain the “war of the currents”<br> please help with at least 1 sentence

Alex777 [14]

Answer:

The war of the currents, sometimes called battle of the currents, was a series of events surrounding the introduction of competing electric power transmission systems in the late 1880s and early 1890s.

Explanation:

3 0

2 years ago

Ammonium nitrate is an ingredient in cold packs used by sports trainers for injured athletes. Calculate the change in temperatur

Ronch [10]

Answer:

See explanation

Explanation:

First, we need to use the correct expression:

Q = m*Cp*ΔT (1)

Q = n*ΔH (2)

These are the 2 expressions to calculate heat or energy.

Now, we want to know the change of temperature of the nitrate in water after being added, so with the innitial data of nitrate, we can calculate heat using the second expression. First, we need to calculate moles with the molecular mass:

n = m/MM

n = 42/80.1 = 0.52 moles

With these moles, we can calculate heat with the ΔH of this reaction:

Q = 0.52 * 25.7 = 13.364 kJ or 13,364 J

However, this heat as is being absorbed, the value would be negative.

Now that we have heat, we can use expression (1) and plug these values to solve for ΔT, but before, we need to know the total mass of the solution (water + nitrate)

m = 250 + 42 = 292 g

now, solving for ΔT:

-13,364 = 292 * 4.18 * ΔT

ΔT = -13,363 / (292 * 4.18)

ΔT = -10.95 °C

3 0

3 years ago