9. Matter is anything that

Why do atomic model has changed over time

Elenna [48]

The model of the atom has dramatically changed over many many years.We learned atoms make up different substances and are the smallest particles of matter, which have subatomic particles that are very small portions of matter. At first scientist only thought there were electrons which are negatively charged.

8 0

2 years ago

In a solution with a pH of 4, the [OH-] is: 1x 10-10 1x 10-4 10 - 1x 10-8

e-lub [12.9K]

Answer:

1 x 10^-4

Explanation:

Use the equation pH = -log[OH-}

Rearranging it [OH-] = 10^-pH

Plugging in we get [OH-] = 1 x 10^-4

3 0

3 years ago

A student prepares a 1.8 M aqueous solution of 4-chlorobutanoic acid (C2H CICO,H. Calculate the fraction of 4-chlorobutanoic aci

Kruka [31]

Answer:

Percentage dissociated = 0.41%

Explanation:

The chemical equation for the reaction is:

$C_3H_6ClCO_2H_{(aq)} \to C_3H_6ClCO_2^-_{(aq)}+ H^+_{(aq)}$

The ICE table is then shown as:

$C_3H_6ClCO_2H_{(aq)} \ \ \ \ \to \ \ \ \ C_3H_6ClCO_2^-_{(aq)} \ \ + \ \ \ \ H^+_{(aq)}$

Initial (M) 1.8 0 0

Change (M) - x + x + x

Equilibrium (M) (1.8 -x) x x

$K_a = \frac{[C_3H_6ClCO^-_2][H^+]}{[C_3H_6ClCO_2H]}$

where ;

$K_a = 3.02*10^{-5}$

$3.02*10^{-5} = \frac{(x)(x)}{(1.8-x)}$

Since the value for $K_a$ is infinitesimally small; then 1.8 - x ≅ 1.8

Then;

$3.02*10^{-5} *(1.8) = {(x)(x)}$

$5.436*10^{-5}= {(x^2)$

$x = \sqrt{5.436*10^{-5}}$

$x = 0.0073729 \\ \\ x = 7.3729*10^{-3} \ M$

Dissociated form of 4-chlorobutanoic acid = $C_3H_6ClCO_2^- = x= 7.3729*10^{-3} \ M$

Percentage dissociated = $\frac{C_3H_6ClCO^-_2}{C_3H_6ClCO_2H} *100$

Percentage dissociated = $\frac{7.3729*10^{-3}}{1.8 }*100$

Percentage dissociated = 0.4096

Percentage dissociated = 0.41% (to two significant digits)

3 0

2 years ago

Read 2 more answers

Which reactions are single displacement reactions? 2NaBr + CaF2 → 2NaF + CaBr2 SnO2 + 2H2 → Sn + 2H2O 4Na + O2 → 2Na2O 2KClO3 →

r-ruslan [8.4K]

Answer : The correct options are, $SnO_2+2H_2\rightarrow Sn+2H_2O$ and $2Al+6HCl\rightarrow 2AlCl_3+3H_2$

Explanation :

Single displacement reaction : It is a type of chemical reaction in which the more reactive element displaces the less reactive element.

Option A reaction : $2NaBr+CaF_2\rightarrow 2NaF+CaBr_2$

It is an example of double displacement reaction because in this reaction a positive cation and a negative anion of the two reactants exchange their places to form two new products.

Option B reaction : $SnO_2+2H_2\rightarrow Sn+2H_2O$

It is an example of single displacement reaction.

Option C reaction : $4Na+O_2\rightarrow 2Na_2O$

It is an example of combination reaction because in this reaction two reactants react to give a single product.

Option D reaction : $2KClO_3\rightarrow 2KCl+3O_2$

It is an example of decomposition reaction because in this reaction a single reactant decomposes into two or more products.

Option E reaction : $2Al+6HCl\rightarrow 2AlCl_3+3H_2$

It is an example of single displacement reaction because in this reaction the most react element, aluminium displaces the less reactive element, hydrogen.

Hence, the options B and E are single displacement reactions.

5 0

3 years ago

Which atoms in the amino acids become the h2o molecule produced by their action in model?

Mariana [72]

Atoms in the amino acids become the h₂O molecule produced by their action in the model and come off from the central carbon and nitrogen but not from the carboxyl, R side chain, or amine.

An amino acid is a group of organic molecules that consist of a basic acidic carboxyl group (―COOH), amino group (―NH2), and an organic R group (or side chain) that is different from each amino acid. Amino acid, the term is a short form of α-amino [alpha-amino] carboxylic acid.

Whereas, the peptide bond is the chemical bond which is a chemical bond formed between two molecules when the carboxyl group of a particular molecule reacts with the amino group of the other molecule, leading to releasing a molecule of water (H2O).

Each molecule consists of a central carbon atom referred to as the α-carbon, to which both a carboxyl group and amino are attached. The remaining two bonds of the α-carbon atom are generally occupied by the R group and a hydrogen (H) atom .

To know more about amino acids refer to the link brainly.com/question/14583479?referrer=searchResults.

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4 0

1 year ago