Find the pH of a solution whose H concentration is 0.7 x 10-3.

A large cyclotron directs a beam of He++ nuclei onto a target with a beam current of 0.250 mA. (a) How many He++ nuclei per seco

nikitadnepr [17]

Answer:

a. 7.8*10¹⁴ He⁺⁺ nuclei/s

b. 4000s

c. 7.7*10⁸s

Explanation:

I = 0.250mA = 2.5 * 10⁻³A

Q = 1.0C

1 e- contains 1.60 * 10⁻¹⁹C

But He⁺⁺ Carrie's 2 charge = 2 * 1.60*10⁻¹⁹C = 3.20*10⁻¹⁹C

(A).

No. Of charge per second = current passing through / charge

1 He⁺⁺ = 2.50 * 10⁻⁴ / 3.2*10⁻¹⁹C

1 He⁺⁺ = 7.8 * 10¹⁴ He⁺⁺ nuclei

(B).

I = Q / t

From this equation, we can determine the time it takes to transfer 1.0C

I = 1.0 / 2.5*10⁻⁴ = 4000s

(C).

Time it takes for 1 mol of He⁺⁺ to strike the target =?

Using Avogadro's ratio,

1.0 mole of He = (6.02 * 10²³ ions/mol ) * (1 / 7.81*10¹⁴ He ions)

Note : ions cancel out leaving the value of the answer in mols.

1.0 mol of He = 7.7 * 10⁸s

8 0

3 years ago

A 360. g iron rod is placed into 750.0 g of water at 22.5°C. The water temperature rises to 46.7°C. What was the initial tempera

Grace [21]

Answer: The initial temperature of the iron was $515^0C$

Explanation:

$heat_{absorbed}=heat_{released}$

As we know that,

$Q=m\times c\times \Delta T=m\times c\times (T_{final}-T_{initial})$

$m_1\times c_1\times (T_{final}-T_1)=-[m_2\times c_2\times (T_{final}-T_2)]$ .................(1)

where,

q = heat absorbed or released

$m_1$ = mass of iron = 360 g

$m_2$ = mass of water = 750 g

$T_{final}$ = final temperature = $46.7^0C$

$T_1$ = temperature of iron = ?

$T_2$ = temperature of water = $22.5^oC$

$c_1$ = specific heat of iron = $0.450J/g^0C$

$c_2$ = specific heat of water= $4.184J/g^0C$

Now put all the given values in equation (1), we get

$-360\times 0.450\times (46.7-x)=[750\times 4.184\times (46.7-22.5)]$

$T_i=515^0C$

Therefore, the initial temperature of the iron was $515^0C$

4 0

3 years ago

Identify what type of reaction is below. Also, determine what coefficients that would balance the chemical equation. ___ C4H10 +

Evgen [1.6K]

This is a combustion reaction because it is being combined with oxygen. Then to balance you will put the number of carbons you have or 4 in front of the CO2 and then same with H2. Then you will add up the oxygen and divide it by two to get. 1, (13/2), 4, 5

7 0

3 years ago

When 0.313 g of Mg is heated strongly in a nitrogen (N2) atmosphere, a chemical reaction occurs. The product of the reaction wei

borishaifa [10]

Answer:

Mg₃N₂ (magnesium nitride)

Explanation:

M(total) = M(mg) + M (n)

M (n) = M(total) - M(mg)

= 0.433g - 0.313g

= 0.12g

mole (N) = 0.12g / 14.0067 g/mol

= 0.008567

mole Mg = 0.313g / 24.3050 g/mol

= 0.012878

Mg = 0.012878 / 0.008567

= 1.5

N = 0.008567 / 0.008567

= 1

multiply by 2 to get whole numbers

Mg = 1.5 × 2 = 3

N = 1 × 2 = 2

Mg₃N₂ (magnesium nitride)

8 0

3 years ago

Give the hybridization for the br in bro4⁻.

elixir [45]

The hybridization for the Br in BrO4⁻ is $sp^{3}$ . So, the correct option is (e).

In chemistry, the idea of combining atomic orbitals to create new hybrid orbitals (with different energies, shapes, etc., than the component atomic orbitals) is known as orbital hybridisation (or hybridization). These new hybrid orbitals are suitable for the pairing of electrons to form chemical bonds in valence bond theory.

Because more directional hybridised orbitals result in higher overlap when creating bonds, stronger bonds are formed, which favours the hybridization of orbitals. When hybridization takes place, this leads to more stable molecules.

One s orbital and three p orbitals combine to form four $sp^{3}$ orbitals, each of which has a 25% s character and a 75% p character. This process is known as $sp^{3}$ hybridization. Anytime an atom is surrounded by four groups of electrons, this kind of hybridization is necessary.

Learn more about hybridization here:

brainly.com/question/12207339

#SPJ4

8 0

1 year ago