4. Since water possess a partially positive and a negative end, we refer to it as?

What is the total number of neutrons in the nucleus of a neutral atom that has 19 electrons and a mass number of 39

zvonat [6]

Answer:

NO OF NEUTRON =MASS NO -ATOMIC NO

=39-19

=20

bcz atomic no is equal to no of electrons

mark as brainliest

7 0

2 years ago

Which property of water best explains why ice forms on its surface

lawyer [7]

The hydrogen bonding tendency of water causes it to be 'sticky,' in that water molecules tend to stick together (as in a puddle). This is known ascohesion. Because of this property, water has a high surface tension. This means that it takes a little extra force to break the surface of the water puddle.Mar 13, 2018

5 0

3 years ago

A compound is 7.74% hydrogen and 92.26% carbon by mass. At 100°C a 0.6883 g sample of the gas occupies 250 mL when the pressure

ycow [4]

Answer: The molecular formula for the compound is $C_6H_6$

Explanation:

We are given:

Percentage of C = 92.26 %

Percentage of H = 7.74 %

Let the mass of compound be 100 g. So, percentages given are taken as mass.

Mass of C = 92.26 g

Mass of H = 7.74 g

To formulate the empirical formula, we need to follow some steps:

Step 1: Converting the given masses into moles.

Moles of Carbon = $\frac{\text{Given mass of Carbon}}{\text{Molar mass of Carbon}}=\frac{92.26g}{12g/mole}=7.68moles$

Moles of Hydrogen = $\frac{\text{Given mass of Hydrogen}}{\text{Molar mass of Hydrogen}}=\frac{7.74g}{1g/mole}=7.74moles$

Step 2: Calculating the mole ratio of the given elements.

For the mole ratio, we divide each value of the moles by the smallest number of moles calculated which is 7.68 moles.

For Carbon = $\frac{7.68}{7.68}=1$

For Hydrogen = $\frac{7.74}{7.68}=1$

Step 3: Taking the mole ratio as their subscripts.

The ratio of C : H = 1 : 1

The empirical formula for the given compound is $CH$

Calculating the molar mass of the compound:

To calculate the molecular mass, we use the equation given by ideal gas equation:

PV = nRT

Or,

$PV=\frac{m}{M}RT$

where,

P = pressure of the gas = 820 torr

V = Volume of gas = 250 mL = 0.250 L (Conversion factor: 1 L = 1000 mL )

m = mass of gas = 0.6883 g

M = Molar mass of gas = ?

R = Gas constant = $62.3637\text{ L. torr }mol^{-1}K^{-1}$

T = temperature of the gas = $100^oC=(100+273)K=373K$

Putting values in above equation, we get:

$820torr\times 0.250L=\frac{0.6883g}{M}\times 62.3637\text{ L torr }mol^{-1}K^{-1}\times 373K\\\\M=\frac{0.6883\times 62.3637\times 373}{820\times 0.250}=78.10g/mol$

For determining the molecular formula, we need to determine the valency which is multiplied by each element to get the molecular formula.

The equation used to calculate the valency is:

$n=\frac{\text{Molecular mass}}{\text{Empirical mass}}$

We are given:

Mass of molecular formula = 78.10 g/mol

Mass of empirical formula = 13 g/mol

Putting values in above equation, we get:

$n=\frac{78.10g/mol}{13g/mol}=6$

Multiplying this valency by the subscript of every element of empirical formula, we get:

$C_{(1\times 6)}H_{(1\times 6)}=C_6H_6$

Hence, the molecular formula for the compound is $C_6H_6$

8 0

3 years ago

What is the boiling point of silver?

vladimir1956 [14]

Answer:

3,924°F

Explanation:

here is the answer it is a little hard to explain but hopeing it helps you a lot

4 0

2 years ago

Read 2 more answers

A stretched spring has an elastic potential energy of 35 J when it is stretched 0.54 m. What is the spring constant of the sprin

Varvara68 [4.7K]

Answer:

240 N/m

Explanation:

Using the formula as follows:

U = ½kx²

Where;

U = elastic potential energy (J)

K = spring constant (N/m)

x = stretched displacement (m)

According to the information provided in this question,

U = 35J

x = 0.54m

k = ?

U = ½kx²

35 = ½ × k × 0.54²

35 = ½ × k × 0.2916

35 = 0.2916k/2

70 = 0.2916k

k = 70 ÷ 0.2916

k = 240.05

To 2s.f, the spring constant (k) = 240 N/m.

6 0

3 years ago