Question 4

The table below gives the numbers of protons, electrons, and neutrons in four atoms.

PolarNik [594]

Answer:

Atom 3

Explanation:

Protons have a +1 charge, electrons have a -1 charge, and neutrons have no charge and are therefore neutral. The charges will cancel each other when equal. To determine which atom has the a -1 charge, find the atom that has one more electron than it has protons.

4 0

2 years ago

Read 2 more answers

HELP PLEASE!!

AleksandrR [38]

Answer:

The mass of the object would be 491.55g/mL. Hope this helped! :)

Explanation:

D= 7.25g/mL M=D•V

V= 67.8mL

M=7.25g/mL•67.8mL

M= 491.55g

8 0

3 years ago

What is the molar mass to Ca3(Po4)2

-Dominant- [34]

P (phosphorous ) = 30.97 g/mol * 2 = 61.94 g/mol.
O ( oxygen ) = 16.00 g/mol * 8 = 128.00 g/mol.
-----------------------------------------------------------+
Calcium Phosphate Ca3(PO4)2 = 310.18 g/mol.

4 0

3 years ago

According to the experimental procedure of Experiment F1, 135 microliters of acetophenone (120.15 g/mol, 1.03 g/mL) was reacted

Delicious77 [7]

Answer: The theoretical yield of 4-nitrochalcone is, $2.13\times 10^2$

Explanation : Given,

Volume of acetophenone = 135 microliters = 135 × 10⁻⁶ L = 0.135 mL

conversion used : (1 microliter = 10⁻⁶ L) and (1 L = 1000 mL)

Density of acetophenone = 1.03 g/mL

Mass of acetophenone = Density × Volume = 1.03 g/mL × 0.135 mL = 0.139 g

Mass of 4-nitrobenzaldehyde = 127 mg = 0.127 g

Conversion used : (1 mg = 0.001 g)

First we have to calculate the moles of acetophenone and 4-nitrobenzaldehyde

$\text{Moles of acetophenone}=\frac{\text{Given mass acetophenone}}{\text{Molar mass acetophenone}}$

$\text{Moles of acetophenone}=\frac{0.139g}{120.15g/mol}=0.00116mol$

and,

$\text{Moles of 4-nitrobenzaldehyde}=\frac{\text{Given mass 4-nitrobenzaldehyde}}{\text{Molar mass 4-nitrobenzaldehyde}}$

$\text{Moles of 4-nitrobenzaldehyde}=\frac{0.127g}{151.12g/mol}=0.000840mol$

Now we have to calculate the limiting and excess reagent.

The balanced chemical equation is:

$C_8H_8O+C_7H_5NO_3\rightarrow C_{15}H_{11}NO_3$

From the balanced reaction we conclude that

As, 1 mole of 4-nitrobenzaldehyde react with 1 mole of acetophenone

So, 0.000840 mole of 4-nitrobenzaldehyde react with 0.000840 mole of acetophenone

From this we conclude that, acetophenone is an excess reagent because the given moles are greater than the required moles and 4-nitrobenzaldehyde is a limiting reagent and it limits the formation of product.

Now we have to calculate the moles of 4-nitrochalcone

From the reaction, we conclude that

As, 1 mole of 4-nitrobenzaldehyde react to give 1 mole of 4-nitrochalcone

So, 0.000840 mole of 4-nitrobenzaldehyde react to give 0.000840 mole of 4-nitrochalcone

Now we have to calculate the mass of 4-nitrochalcone

$\text{ Mass of 4-nitrochalcone}=\text{ Moles of 4-nitrochalcone}\times \text{ Molar mass of 4-nitrochalcone}$

Molar mass of 4-nitrochalcone = 253.25 g/mole

$\text{ Mass of 4-nitrochalcone}=(0.000840moles)\times (253.25g/mole)=0.21273g=212.73mg=2.13\times 10^2mg$

(1 g = 1000 g)

Therefore, the theoretical yield of 4-nitrochalcone is, $2.13\times 10^2mg$

4 0

3 years ago

Which is a property of covalent compounds?

ira [324]

Answer:

Explanation:

The properties of covalent bonds are:

1. Low boiling points and melting points.

2. Various colors.

3. Poor conductors of heat and electricity.

4. Brittle solids.

6 0

2 years ago