A thin sheet of aluminum can block ____

Which one of the following statements is FALSE? a In a neutralization reaction, an acid reacts with base to produce a salt and H

pishuonlain [190]

Answer: Option (c) is the correct answer.

Explanation:

HF is a weak acid and not a strong acid. This is because fluorine is a highly electronegative atom and when it combines with a hydrogen atom then it will attract the valence electron of hydrogen atom more towards itself.

As a result, it will not dissociates easily to give hydrogen ion. Hence, it acts as a weak acid.

A neutralization reaction is defined as a reaction in which an acid reacts with a base to give salt and water. For example, $HCl + NaOH \rightarrow NaCl + H_{2}O$

It is true that, spectator ions "appear in the total ionic equation for a reaction, but not in the net ionic equation".

Titration is defined as a process in which concentration of an unknown solution is determined using a solution of known concentration.

Thus, we can conclude that the statement HF, HCl, and HNO3 are all examples of strong acids, is false.

7 0

3 years ago

A chemistry teacher is able to grade chemistry labs at a rate of 5 labs for every 3 minutes. They need to grade 165 labs how man

PIT_PIT [208]

Answer:

1.65hr

Explanation:

Given parameters:

Number of labs = 5 labs

Time taken = 3 minutes

Unknown:

Time taken in hours to grade 165 labs = ?

Solution:

Let us find the rate of the teacher;

Rate = $\frac{number of labs}{time}$

Insert the parameters and solve;

Rate = $\frac{5}{3}$ = 1.67labs/min

Now;

Time to grade 165 labs = $\frac{number of labs}{rate}$

Time to grade 165 labs = $\frac{165}{1.67}$ = 98.8min

Since;

60min = 1hr

98.8min = $\frac{98.8}{60}$ = 1.65hr

3 0

3 years ago

can any body tell me what is the relation in between halogen group and van der wals foce of attraction.why it increase down the

Volgvan

Because the size of atoms increase as you move down the periodic table.

5 0

3 years ago

Read 2 more answers

What happens to the molecules of water when the water changes from liquid to gas?.

ICE Princess25 [194]

Answer: Molecules only speed up when given energy, such as heating. When you heat water enough, it will boil and turn into water vapor. So, therefore, if water's molecules speed up, it will go into the gas phase

Explanation: As that liquid water is further heated, it evaporates and becomes a gas—water vapor. These changes between states (melting, freezing, and evaporating) happen because as the temperature either increases or decreases, the molecules in a substance begin to speed up or slow down.

Hope this helps! ^w^

3 0

2 years ago

Androstenedione, which contains only carbon, hydrogen, and oxygen, is a steroid hormone produced in the adrenal glands and the g

Gennadij [26K]

Answer: The molecular formula for androstenedione is, $C_{19}H_{26}O_2$

Explanation:

The chemical equation for the combustion of hydrocarbon having carbon, hydrogen and oxygen follows:

$C_xH_yO_z+O_2\rightarrow CO_2+H_2O$

where, 'x', 'y' and 'z' are the subscripts of Carbon, hydrogen and oxygen respectively.

We are given:

Mass of $CO_2=5.527g$

Mass of $H_2O=1.548g$

We know that:

Molar mass of carbon dioxide = 44 g/mol

Molar mass of water = 18 g/mol

For calculating the mass of carbon:

In 44 g of carbon dioxide, 12 g of carbon is contained.

So, in 5.527 g of carbon dioxide, $\frac{12}{44}\times 5.527=1.507g$ of carbon will be contained.

For calculating the mass of hydrogen:

In 18 g of water, 2 g of hydrogen is contained.

So, in 1.548 g of water, $\frac{2}{18}\times 1.548=0.172g$ of hydrogen will be contained.

For calculating the mass of oxygen:

Mass of oxygen in the compound = $(1.893g)-[(1.507g)+(0.172g)]=0.214g$

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

Step 1: Converting the given masses into moles.

Moles of Carbon = $\frac{\text{Given mass of Carbon}}{\text{Molar mass of Carbon}}=\frac{1.507g}{12g/mole}=0.126moles$

Moles of Hydrogen = $\frac{\text{Given mass of Hydrogen}}{\text{Molar mass of Hydrogen}}=\frac{0.172g}{1g/mole}=0.172moles$

Moles of Oxygen = $\frac{\text{Given mass of oxygen}}{\text{Molar mass of oxygen}}=\frac{0.214g}{16g/mole}=0.0133moles$

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 $0.0133$ moles.

For Carbon = $\frac{0.126}{0.0133}=9.5$

For Hydrogen = $\frac{0.172}{0.0133}=12.9\approx 13$

For Oxygen = $\frac{0.0133}{0.0133}=1$

Step 3: Taking the mole ratio as their subscripts.

The ratio of C : H : O = 9.5 : 13 : 1

To make in a whole number we are multiplying the ratio by 2, we get:

The ratio of C : H : O = 19 : 26 : 2

Thus, the empirical formula for the given compound is $C_{19}H_{26}O_2$

The empirical formula weight of $C_{19}H_{26}O_2$ = 19(12) + 26(1) + 2(16) = 286 gram/eq

Now we have to calculate the molecular formula of the compound.

Formula used :

$n=\frac{\text{Molecular formula}}{\text{Empirical formula weight}}$

$n=\frac{286.4}{286}=1$

Molecular formula = $C_{19}H_{26}O_2$

Therefore, the molecular formula for androstenedione is, $C_{19}H_{26}O_2$

3 0

3 years ago

A thin sheet of aluminum can block _____.