Suppose you have 81.8 g of cd. how many cd atoms are present? report your answer in scientific notation using the format of 6.022e23 for 6.022 x 1023.

suppose you have 39.1 g of ti. what number of moles of ti is present?

salicylic acid has the formula c7h6o3. what is the molar mass of salicylic acid?

sildenafil, sold as the brand name viagra among others, has a molar mass of 474.5828. suppose you have 0.118 g of sildenafil. how many moles of sildenafil are present? report your answer to 3 significant figures. if you choose to use scientific notation in reporting your answer, use the format of 6.022e23 for 6.022 × 1023

1. number of Cd atoms = 4.384 × 10²³

2. number of moles of Ti = 0.817 mol

3. molar mass of C₇H₆O₃ = 138.077 g/mol

4. moles of Sildenafil = 0.249 mmol

Explanation:

1. given data

mass of Cd = 81.8 g

number of Cd atoms = ?

molar mass of Cd = 112.411 g/mol

Solution

1st we find out the number of moles of Cd

        number of moles = mass / molar mass

 number of moles of Cd = 81.8 g / 112.411 g.mol⁻

 number of moles of Cd = 0.728 mol

Now we find out the number of Cd atoms

      number of atoms = moles × 6.022 × 10²³

 number of Cd atoms = 0.728 (6.022 × 10²³)

 number of Cd atoms = 4.384 × 10²³

2. Given data

Mass of Ti = 39.1 g

moles = ?

molar mass Ti = 47.867 g/mol

Solution

Now we will find out the number of moles

        number of moles = mass / molar mass

 number of moles of Ti = 39.1 g / 47.867 g.mol⁻

 number of moles of Ti = 0.817 mol

3. Given data

chemical formula of Salicylic acid  = C₇H₆O₃

molar mass of salicylic acid = ?

molar mass of carbon = 12.011

molar mass of hydrogen = 1.008

molar mass of oxygen = 15.999

        molar mass of  molecule = number of moles of atoms × molar mass of atoms

  molar mass of C₇H₆O₃ = 7 (12.011) + 6 (1) + 3 (16)

  molar mass of C₇H₆O₃ = 84.077 g + 6 g + 48 g

  molar mass of C₇H₆O₃ = 138.077 g/mol

4. Given data

molar mass of Sildenafil = 474.5828 g/mol

mass given = 0.118 g

moles of Sildenafil = ?

Solution

Now we find out the number of moles

         number of moles = mass / molar mass

  number of moles Sildenafil = 0.118 g / 474.5828 g/mol

  number of moles Sildenafil = 0.0003 mol

as this is very small amount we convert it into millimoles

           millimoles = moles × 1000

    millimoles of Sildenafil = 0.000249 × 1000

    millimoles of Sildenafil = 0.249 mmol

when 25.0 ml of 0.700 mol/l naoh was mixed in a calorimeter with 25.0 ml of 0.700 mol/l hcl, both initially at 20.0 °c, the temperature increased to 22.1 °c. the heat capacity of the calorimeter is 279 j/°c.

the equation for the reaction is:

naoh + hcl → nacl + h₂o

moles of hcl = 0.0250 l hcl ×

0.700

mol hcl

1 l hcl = 0.0175 mol hcl

volume of solution = (25.0 + 25.0) ml = 50.0 ml

mass of solution = 50.0 ml soln ×

1.00

ml soln

= 50.0 g soln

δt=t2-t1

= (22.1 – 20.0) °c = 2.1 °c

the heats involved are

heat from neutralization + heat to warm solution + heat to warm calorimeter = 0

q1+q2+q3=0

nδh+mcδt+cδt=0

0.0175 mol ×

δh

+ 50.0 g × 4.184 j·g⁻¹°c⁻¹ × 2.1 °c + 279 j°c⁻¹ × 2.1 °c = 0

0.0175 mol ×

δh

+ 439.32 j + 585.9 j = 0

0.0175 mol ×

δh

= -1025.22 j

δh=1025.22j0.0175 mol= -58 600 j/mol = -58.6 kj/mol

i think the answer is terrae but not 100 percent sure. ▓▬▬ §