The time needed for a radioactive sample to decay to one-half of its original activity is called the _______

aspirin is a compound that contain carbon,hydrogen and oxygen. It is uesd as painkiller. An aspirin tablet contain 1.25×10³⁰ mol

igomit [66]

Use formula n= number of particles / avogrado constant

n= number of mole
avogrado constant= 6.12x10^-23

you will get 2.042 x 10^52

5 0

4 years ago

A titration of 0.1 M NaOH into 1.2 L of HCl was stopped once the pH reached 7 (at 25C). If 0.4 L of NaOH needed to be added to a

MArishka [77]

Answer:

0.033 M

Explanation:

Let's consider the neutralization reaction between NaOH and HCl.

NaOH + HCl → NaCl + H₂O

0.4 L of 0.1 M NaOH were used. The reacting moles of NaOH are:

0.4 L × 0.1 mol/L = 0.04 mol

The molar ratio of NaOH to HCl is 1:1. The reacting moles of HCl are 0.04 moles.

0.04 moles of HCl are in 1.2 L. The molarity of HCl is:

M = 0.04 mol / 1.2 L = 0.033 M

4 0

3 years ago

PLZ HELP ...The half-life of polonium-218 is 3.0 minutes. If you start with 40.0 g, how long will it be before only 4.5 g remain

Elanso [62]

Answer:- 9.4 minutes.

Solution:- Radioactive decay obeys first order reaction kinetics and the equation used to solve this type of problems is:

$lnN=-kt+lnN_0$

where, k is decay constant and t is the time. $N_0$ is the initial amount of the radioactive substance and N is the remaining amount.

Since the value of decay constant is not given, so we need to calculate it first from given half life by using the formula:

$k=\frac{0.693}{t_1_/_2}$

where $t_1_/_2$ stands for half life.

Given half life is 3.0 minutes.

So, $k=\frac{0.693}{3.0min}$

$k=0.231min^-^1$

Let's plug in the values in the first order reaction equation and solve it for t.

$ln4.5g=-0.231min^-^1(t)+ln40.0g$

It could also be written as:

$ln(\frac{4.5g}{40.0g})=-0.231min^-^1}$

$-2.18=-0.231min^-^1}$

$t=\frac{-2.18}{-0.231min^-^1}$

k = 9.4 min

So, the radioactive substance would take 9.4 minutes to decay from 40.0 grams to 4.5 grams.

4 0

3 years ago

The wavelength of the violet light emitted from a hydrogen atom is 410.1 nm. This light is a result of electronic transitions be

VashaNatasha [74]

Answer:

e. 4.847 x 10-19 J

Explanation:

From the given information:

The equation connecting the photon energy and the wavelength is:

$E_{photon } = \dfrac {hc}{\lambda}$

where;

$planck's \ constant \ (h)$ = 6.626 * 10 ^{-34} J.s

$velocity \ of \ light \ (c)$ = 3.00 * 10^8 m/s

wavelength $\lambda = 410.1 \ nm \times \dfrac{10^{-9} \ m}{1 \ nm}$

$\lambda = 4.101 \times 10^{-7} \ m$

To determine the photon energy of violet light

$E_{photon } = \dfrac {(6.626 \times 10^{-34} J/s ) \times (3.00 \times 10^8 \ m/s) }{4.101 \times 10^{-7} \ m}$

= 4.847 × 10⁻¹⁹ J

4 0

3 years ago

How many significant figures will be in the final answer of this calculation? 20.2 + 3.10 - 0.09687 = ________

Lana71 [14]

There will be seven characters so the answer is e

4 0

3 years ago

The time needed for a radioactive sample to decay to one-half of its original activity is called the ________.