Which of these prevents conduction from occuring?

What percent of an original sample remains after 3 half-lives? After 5 half-lives?

Salsk061 [2.6K]

Answer:

Three half lives corresponds to (12)3 . So a 18 quantity of the original isotope is retained. And the percentage of quantity of a radioactive material that remains after 5 half-lives will be . ∴NN0×100=10032=3.125.

7 0

4 years ago

Muriatic acid, an industrial grade of concentrated HCl, is used to clean masonry and cement. Its concentration is 11.7 M. For ro

Nata [24]

Answer:

$\boxed{\text{199 mL}}$

Explanation:

1. Calculate the moles of HCl

$n = \text{25.4 g} \times \dfrac{\text{1 mol}}{\text{36.46 g}} = \text{0.6967 mol}$

2. Calculate the volume of dilute HCl

$\begin{array}{rcl}\text{Molar concentration}& =& \dfrac{\text{moles}}{\text{litres}}\\\\3.50 & = & \dfrac{0.6967}{V}\\\\3.50V & = & 0.6967\\\\V & = & \dfrac{0.6967}{3.50}\\\\V & = & \text{0.199 L} =\textbf{199 mL}\end{array}\\\text{The volume of muriatic acid needed is }\boxed{\textbf{199 mL}}$

3 0

3 years ago

What is the orientation of the two unhybridized p orbitals on Be with respect to the two Be−F bonds?

Len [333]

Answer:

b) Both p orbitals are perpendicular to the F−Be−F bond axes.

Explanation:

Be has 2 electrons in its valence shell, subshell s is fulfilled, so it has no unpaired electrons in its ground state to make bonds with F. So, it can promote the electrons to the 2p orbital and will having sp hybridization.

The bond between the orbitals sp and the p orbital of F are in opposite directions but the same ax. The two bonds are equivalent, and the molecule had a linear geometry. The two unhybridized p orbitals on Be are vacant, and so they are perpendicular to the F-Be-F bond axes.

7 0

4 years ago

Why can iron be broken down into atoms, but water can only be broken down to molecules?

rodikova [14]

Iron is matter; since the smallest unit of matter is atoms, iron could be brokolen down into atoms. unlike iron, water is a molecule made from atoms that were chemically combined, so water could be broken down into molecules.

8 0

4 years ago

Hi everyone, I'm really stuck on a question for my uni assignment, i just dont understand chemistry at all, i was wondering if a

sdas [7]

<h3>Answer : 2C + 3H2 -> C2H6</h3>

<h3>Step and explanation</h3>

Condition : graphite + hydrogen gas

Chemical formula : C + H2

Reaction formula :

C + H2 -> C2H6

#First, you see the number of atom

•Product

C = 1

H = 2

•Reactant

C = 2

H = 6

#Note that, in a chemical reaction both number of each atom in product must be equal in reactant so, you think what number you need to put Infront of the chemical formula so that the number of atom equal

2C + 3H2 -> C2H6

#Now check again

•Product

C = 2

H = 6

•Reactant

C = 2

H6

#Now, its equal. The bold one is the balance chemical reaction

<h3>Note (just incase u dont know)</h3>

Reactant -> product (the thing you get after reaction)

7 0

3 years ago