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2 years ago

What are the units for the measurements of radioactive element activity?

Chemistry

1 answer:

torisob [31]2 years ago

7 0

Answer:

Explanation:

The number of decays per second, or activity, from a sample of radioactive nuclei is measured in becquerel (Bq), after Henri Becquerel. One decay per second equals one becquerel.

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The property of a substance stays ______________ no matter how the substance is used.

Irina18 [472]

Any substance changes to another substance that means the change of the physical property. Like water () has different state which changes as the temperature changes. It remain as liquid in the room temperature, in solid form at or below 0°C and vapor phase on or above 100°C. But in all the stage or phase of the substance the composition of the water i.e. remains. Thus the chemical property remains fixed when a substance change to other substance.

3 0

3 years ago

What is the mass, in grams, of

DIA [1.3K]

Answer:

The answers to your question are below

Explanation:

a) 6.85×1020 H2O2 molecules

H2O2 MW = 32 + 2 = 34 g

34g -------------------- 6.023 x 10²³ molecules

x ------------------- 6.85 x 10 ²⁰

x = (6.85 x 10 ²⁰)(34)/ 6.023 x 10²³

x = 0.038 g

3.3×1022 SO2 molecules

MW SO2 = 32 + 32 = 64g

64 g -------------------- 6.023 x 10²³ molecules

x -------------------- 3.3×1022 SO2 molecules

x = (3.3×1022 SO2)(64) / 6.023 x 10²³

x = 3.51 g

5.5×1025 O3 molecules

MW = 16 x 3 = 48g

48 g ----------------- 6.023 x 10²³ molecules

x ------------------ 5.5×1025 O3 molecules

x = (5.5×1025 )(48) / 6.023 x 10²³

x = 4383 g

9.30×1019 CH4 molecules

MW = 12 + 4 = 16 g

16 g -------------------- 6.023 x 10²³ molecules

x -------------------- 9.30×1019 CH4 molecules

x = (9.30×1019)(16) / 6.023 x 10²³

x = 0.0025 g

4 0

2 years ago

Why does mecury hardly evaporate in room temperature

Crazy boy [7]

Because elemental mercury is a liquid at a room temperature

6 0

2 years ago

The decomposition of N2O4 into NO2 has Kp = 2. Some N2O4 is placed into an empty container, and the partial pressure of NO2 at e

Sunny_sXe [5.5K]

Answer: Option (B) is the correct answer.

Explanation:

Expression for the given decomposition reaction is as follows.

$N_{2}O_{4} \rightarrow 2NO_{2}$

Let us assume that x concentration of $N_{2}O_{4}$ is present at the initial stage. Therefore, according to the ICE table,

$N_{2}O_{4} \rightarrow 2NO_{2}$

Initial : x 0

Change : - 0.1 $2 \times 0.1$

Equilibrium : (x - 0.1) 0.2

Now, expression for $K_{p}$ of this reaction is as follows.

$K_{p} = \frac{P^{2}_{NO_{2}}}{P_{N_{2}O_{4}}}$

Putting the given values into the above formula as follows.

$K_{p} = \frac{P^{2}_{NO_{2}}}{P_{N_{2}O_{4}}}$

$2 = \frac{(0.2)^{2}}{(x - 0.1)}$

$2 \times (x - 0.1) = (0.2)^{2}$

x = 0.12

This means that $P_{N_{2}O_{4}}$ = x = 0.12 atm.

Thus, we can conclude that the initial pressure in the container prior to decomposition is 0.12 atm.

6 0

2 years ago

Construct a three-step synthesis of trans-2-pentene from acetylene by dragging the appropriate formulas into the bins. Note that

adelina 88 [10]

Answer:

The three-step synthesis of trans-2-pentene from acetylene is as follows.

Step -1: Formation of higher order terminal alkyne on reaction with sodium acetylides with haloalkanes.

Step -2: Formation terminal alkyne to nonterminal alkynes.

Step -3: Formation of trans-pent - 2-pent-ene by reduction.

Explanation:

Synthesis of trans-pent-2-yne from ethyne takes place is mainly a three step synthesis which involves formation of higher order terminal alkyne on reaction with sodium acetylides with haloalkane. Second step involves the further alkylation of terminal alkynes to higher order nonterminal alkynes and the third step involves the formation of trans-2-ene by dissolving reduction method.

The chemical reaction of each step of chemical reactions is as follows.

8 0

2 years ago