Ask question

Ask question

All categories

3 years ago

8

A sample of polonium-210 has an initial mass of 390 milligrams (mg). If the half-life of polonium-210 is 36 days, how many mg of

the sample remains after 72 days?
A.
392 mg

B.
195 mg

C.
97.5 mg

D.
48.75 mg

1 answer:

Over [174]3 years ago

3 0

Answer:

C

Explanation:

I got this question right on my test.

You might be interested in

The charge per unit length on a glass rod is 0.00500 C/m. If the rod is 1 mm long, how many electrons have been removed from the

ehidna [41]

Answer:

3.125 × 10¹³ Electrons

Explanation:

Data provided in the question:

Charge per unit length on rod = 0.00500 C/m

Length of the rod = 1 mm = 1 × 10⁻³ m

Therefore, the total charge on the rod

= Charge per unit length on rod × Length of the rod

= 0.00500 C/m × ( 1 × 10⁻³ m)

= 5 × 10⁻⁶ C

Thus,

Number of electrons removed

= total charge on the rod ÷ Charge of an electron

= 5 × 10⁻⁶ ÷ (1.6 × 10⁻¹⁹)

= 3.125 × 10¹³ Electrons

5 0

4 years ago

What is the attractive force that occurs between the sun and the earth called? friction magnetism weight gravity

natima [27]

I believe the correct answer from the choices listed above is the last option. The attractive force that occurs <span>between the sun and the earth is called gravity. Hope this answers the question. Have a nice day. Feel free to ask more questions.</span>

3 0

3 years ago

Read 2 more answers

What is cell theory and how is it applied to all living organisms?

ch4aika [34]

Description in biology, cell theory is the historic scientific theory, now universally accepted, that living organisms are made up of cells, that they are the basic structural/organizational unit of all organisms, and that all cells come from pre-existing cells.

4 0

3 years ago

5Br−+BrO3−+6H+→3Br2+3H2O

sashaice [31]

Explanation :

The balanced chemical reaction is,

$5Br^-+BrO_3^-+6H^+\rightarrow 3Br_2+3H_2O$

The expression for the rates of consumption of the reactants are:

The rate of consumption of $Br^-$ = $-\frac{1}{5}\frac{d[Br^-]}{dt}$

The rate of consumption of $BrO_3^-$ = $-\frac{d[BrO_3^-]}{dt}$

The rate of consumption of $H^+$ = $\frac{1}{6}\frac{d[H^+]}{dt}$

The expression for the rates of formation of the products are:

The rate of consumption of $Br_2$ = $+\frac{1}{3}\frac{d[Br_2]}{dt}$

The rate of consumption of $H_2O$ = $+\frac{1}{3}\frac{d[H_2O]}{dt}$

5 0

3 years ago

a compound has an empirical formula of CH2 what is the molecular formula if it's molar mass is 252.5 grams/mol

Goryan [66]

Empirical formula is the simplest ratio of components making up the compound. the molecular formula is the actual ratio of components making up the compound.

the empirical formula is CH₂. We can find the mass of CH₂ one empirical unit and have to then find the number of empirical units in the molecular formula.

Mass of one empirical unit - CH₂ - 12 g/mol x 1 + 1 g/mol x 2 = 12 = 14 g

Molar mass of the compound is - 252 .5 g/mol

number of empirical units = molar mass / mass of empirical unit

= $\frac{252.5 g/mol}{14 g}$

= 18 units

Therefore molecular formula is - 18 times the empirical formula

molecular formula - CH₂ x 18 = C₁₈H₃₆

molecular formula is C₁₈H₃₆

8 0

3 years ago