What is the type of decay chain involved radon 222?

Calculate the heat change in calories for melting 65 g of ice at 0 ∘c.

Genrish500 [490]

When ice melts, the physicals state changes from solid to liquid. The energy or the heat required (q) required to change a unit mass (m) of a substance from solid to liquid is known as the enthalpy or heat of fusion (ΔHf). The variables; q, m and ΔHf are related as:

q = m * ΔHf

the mass of ice m = 65 g

the heat of fusion of water at 0C = ΔHf = 334 J/g

Therefore: q = 65 g * 334 J/g = 21710 J

Now:

4.184 J = 1 cal

which implies that: 21710 J = 1 cal * 21710 J/4.184 J = 5188.8 cal

Hence the heat required is 5188.8 cal or 5.2 Kcal (approx)

5 0

3 years ago

A certain material has a mass of 12.48 g while occupying 12.48 cm3 of space. What is this material?

Salsk061 [2.6K]

This material has a density of 1 g/cm3.
(since 12.48 g/ 12.48 cm3 = 1 g/cm3)

Therefore, this material is water.

5 0

3 years ago

Read 2 more answers

Carbon dioxide in the oceans is affecting its pH. a. True b. False

monitta

Its true it affects the pH balance

7 0

2 years ago

Describe the radial velocity curve. What is its shape? What is its amplitude? What is the orbital period?

lutik1710 [3]

Answer:

The radial velocity curve describes how fast a star is moving in its orbit around a center of mass ( m )

Curve amplitude : This is the maximum value of the radial velocity curve

Radial velocity shape ; The shape of Radial velocity curve is parabolic in nature

Orbital period : Orbital period is the time taken by the star to make one complete rotation in its orbit

Explanation:

The radial velocity curve describes how fast a star is moving in its orbit around a center of mass ( m ) while Curve amplitude is the maximum value of the radial velocity curve also The shape of Radial velocity curve is parabolic in nature. and Orbital period is the time taken by the star to make one complete rotation in its orbit

7 0

3 years ago

In order to prepare very dilute solutions, a lab technician chooses to perform a series of dilutions instead of measuring a very

SVETLANKA909090 [29]

Answer: The final concentration of potassium nitrate is $5.70\times 10^{-6}M$

Explanation:

To calculate the molecular mass of solute, we use the equation used to calculate the molarity of solution:

$\text{Molarity of the solution}=\frac{\text{Mass of solute}\times 1000}{\text{Molar mass of solute}\times \text{Volume of solution (in mL)}}$

We are given:

Mass of potassium nitrate (solute) = 0.360 g

Molar mass of potassium nitrate = 101.1 g/mol

Volume of solution = 500.0 mL

Putting values in above equation, we get:

$\text{Molarity of }KNO_3=\frac{0.360\times 1000}{101.1\times 500.0}\\\\\text{Molarity of }KNO_3=7.12\times 10^{-3}M$

To calculate the molarity of the diluted solution, we use the equation:

$M_1V_1=M_2V_2$ .......(1)

Calculating for first dilution:

$M_1\text{ and }V_1$ are the molarity and volume of the concentrated $KNO_3$ solution

$M_2\text{ and }V_2$ are the molarity and volume of diluted $KNO_3$ solution

We are given:

$M_1=7.12\times 10^{-3}M\\V_1=10mL\\M_2=?M\\V_2=500.0mL$

Putting values in equation 1, we get:

$7.12\times 10^{-3}\times 10=M_2\times 500\\\\M_2=\frac{7.12\times 10^{-3}\times 10}{500}=1.424\times 10^{-4}M$

Calculating for second dilution:

$M_2\text{ and }V_2$ are the molarity and volume of the concentrated $KNO_3$ solution

$M_3\text{ and }V_3$ are the molarity and volume of diluted $KNO_3$ solution

We are given:

$M_2=1.424\times 10^{-4}M\\V_2=10mL\\M_3=?M\\V_3=250.0mL$

Putting values in equation 1, we get:

$1.424\times 10^{-4}\times 10=M_3\times 250\\\\M_3=\frac{1.424\times 10^{-4}\times 10}{250}=5.70\times 10^{-6}M$

Hence, the final concentration of potassium nitrate is $5.70\times 10^{-6}M$

8 0

3 years ago