All categories

3 years ago

How many answered does this question have , and which ?

Chemistry

1 answer:

Leviafan [203]3 years ago

4 0

X rays and Gamma Rays.

You might be interested in

Submit Quiz Previous Page 1 of 4 Next Drag and drop each description to match the subatomic particle. Protons Neutrons Drag and

Pavel [41]

Answer:

Protons:

Positively charged particle

The number of these is the atomic number

All atoms of a given element have the same number of these

Neutrons:

Neutral particles

Isotopes of a given element differ in the number of these

The mass number is the number of these added to the number of protons

Explanation:

Protons (positively charged), neutrons (neutral) and electrons (negatively charged) are smaller than an atom and they are the main subatomic particles. The nucleus of an atom is composed of protons and neutrons, and the electrons are in the periphery at unknown pathways.

The Atomic number (Z) indicates the number of protons ( $P^{+}$ ) in the nucleus. Every atom of an element have the same atomic number, thus the same number of protons.

The mass number (A) is the sum of the number of protons ( $P^{+}$ ) and neutrons (N) that are present in the nucleus: A= Z + N

Isotopes are atoms of the same element which nucleus have the same atomic number (Z), and different mass number (A), it means the same number of protons ( $P^{+}$ ) and a different number of neutrons (N). For example, the oxygen in its natural state is a mixture of isotopes:

99.8% atoms with A= 16, Z=8, and N=8

0.037% atoms with A=17, Z=8, and N=9

0.204% atoms with A=18, Z=8, and N=10

3 0

3 years ago

What happens to the length of shadows as noon approaches on a sunny day?

Tems11 [23]

Answer:

The answer is D

5 0

3 years ago

Read 2 more answers

How is kinetic energy of particles and temperature related

Rufina [12.5K]

Answer:

The higher the temperature, the faster the particles move, the lower the temperature, the slower.

4 0

3 years ago

What must be the molarity of an aqueous solution of trimethylamine, (ch3)3n, if it has a ph = 11.20? (ch3)3n+h2o⇌(ch3)3nh++oh−kb

Stolb23 [73]

0.040 mol / dm³. (2 sig. fig.)

<h3>Explanation</h3>

$(\text{CH}_3)_3\text{N}$ in this question acts as a weak base. As seen in the equation in the question, $(\text{CH}_3)_3\text{N}$ produces $\text{OH}^{-}$ rather than $\text{H}^{+}$ when it dissolves in water. The concentration of $\text{OH}^{-}$ will likely be more useful than that of $\text{H}^{+}$ for the calculations here.

Finding the value of $[\text{OH}^{-}]$ from pH:

Assume that $\text{pK}_w = 14$ ,

$\begin{array}{ll}\text{pOH} = \text{pK}_w - \text{pH} \\ \phantom{\text{pOH}} = 14 - 11.20 &\text{True only under room temperature where }\text{pK}_w = 14 \\\phantom{\text{pOH}}= 2.80\end{array}$ .

$[\text{OH}^{-}] =10^{-\text{pOH}} =10^{-2.80} = 1.59\;\text{mol}\cdot\text{dm}^{-3}$ .

Solve for $[(\text{CH}_3)_3\text{N}]_\text{initial}$ :

$\dfrac{[\text{OH}^{-}]_\text{equilibrium}\cdot[(\text{CH}_3)_3\text{NH}^{+}]_\text{equilibrium}}{[(\text{CH}_3)_3\text{N}]_\text{equilibrium}} = \text{K}_b = 1.58\times 10^{-3}$

Note that water isn't part of this expression.

The value of Kb is quite small. The change in $(\text{CH}_3)_3\text{N}$ is nearly negligible once it dissolves. In other words,

$[(\text{CH}_3)_3\text{N}]_\text{initial} = [(\text{CH}_3)_3\text{N}]_\text{final}$ .

Also, for each mole of $\text{OH}^{-}$ produced, one mole of $(\text{CH}_3)_3\text{NH}^{+}$ was also produced. The solution started with a small amount of either species. As a result,

$[(\text{CH}_3)_3\text{NH}^{+}] = [\text{OH}^{-}] = 10^{-2.80} = 1.58\times 10^{-3}\;\text{mol}\cdot\text{dm}^{-3}$ .

$\dfrac{[\text{OH}^{-}]_\text{equilibrium}\cdot[(\text{CH}_3)_3\text{NH}^{+}]_\text{equilibrium}}{[(\text{CH}_3)_3\text{N}]_\textbf{initial}} = \text{K}_b = 1.58\times 10^{-3}$ ,

$[(\text{CH}_3)_3\text{N}]_\textbf{initial} =\dfrac{[\text{OH}^{-}]_\text{equilibrium}\cdot[(\text{CH}_3)_3\text{NH}^{+}]_\text{equilibrium}}{\text{K}_b}$ ,

$[(\text{CH}_3)_3\text{N}]_\text{initial} =\dfrac{(1.58\times10^{-3})^{2}}{6.3\times10^{-5}} = 0.040\;\text{mol}\cdot\text{dm}^{-3}$ .

8 0

3 years ago

Isotonic compound have high melting point. Why ? Name the ions present in CaS.

yuradex [85]

Explanation:

Because a large amount of energy is required to break the strong inter-ionic attraction.

CaS => Ca2+ & S2-

3 0

3 years ago