In an atom of argon-40 the number of protons

Crank

This year course engages students in becoming skilled readers of prose written in a variety of periods, disciplines, and

rhetorical contexts and in becoming skilled writers who compose for a variety of purposes. More immediately, the course

prepares the students to perform satisfactorily on the A.P. Examination in Language and Composition given in the spring.

Both their writing and their reading should make students aware of the interactions among a writer’s purposes, audience

expectations, and subjects as well as the way generic conventions and the resources of language contribute to effectiveness

in writing. Students will learn and practice the expository, analytical, and argumentative writing that forms the basis of

academic and professional writing; they will learn to read complex texts with understanding and to write prose of

sufficient richness and complexity to communicate effectively with mature readers. Readings will be selected primarily,

but not exclusively, from American writers. Students who enroll in the class will take the AP examination.

4 0

4 years ago

Identify the information that can be included in a chemical equation. Check all of the boxes that apply. how long the reaction t

Soloha48 [4]

the states of the reactants and products

the temperature and pressure at which the reaction was carried out

the relative amounts of reactants and products

the type of catalyst that is used to speed up the reaction

whether the reaction can go in both directions

Explanation:

A chemical equation is an equation that shows how the reactants are combining together to give the products.

The following are the information to include when writing a chemical equation;

the states of the reactants and products

whether solid, liquid or gases or aqueous, It is usually appended as a subscript in bracket

the temperature and pressure at which the reaction was carried out

this shows the condition under which the reaction was carried out. It also gives useful information that can be used to quantitatively determine heat changes in a reaction.

the relative amounts of reactants and products

this is usually derived from the balanced equation. They are the numbers appended at the beginning of the species in the equation

the type of catalyst that is used to speed up the reaction

it is a good practices to provide the information about the catalyst used.

whether the reaction can go in both directions

→ signifies one direction

⇔ both directions

learn more:

Chemical equation brainly.com/question/2924195

#learnwithBrainly

6 0

4 years ago

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What atomic or hybrid orbital on sb makes up the sigma bond between sb and f in antimony(iii) fluoride, sbf3?

Afina-wow [57]

Answer: The four $sp^3$ hybridized orbitals on Sb makes up the sigma bonds between Sb and F in antimony(iii) fluoride , $SbF_3$

Explanation:

According to VESPR theory:

Number of electrons around the central atom : $\frac{1}{2}[V+N-C+A]$

V = number of valence electrons

N = number of neighboring atoms

C = charge on cation

A = charge on an anion

In antimony(III) fluoride ,

Antimony being central atom: V= 5,N =3,C=0,A=0

Number of electrons : $\frac{1}{2}[V+N-C+A]=4$

Number of electrons around the central atom are 4 which means that $SbF_3$ molecule has four $sp^3$ hybridized orbitals.

6 0

3 years ago

Phosphoric acid is a triprotic acid ( K a1 = 6.9 × 10 − 3 Ka1=6.9×10−3, K a2 = 6.2 × 10 − 8 Ka2=6.2×10−8, and K a3 = 4.8 × 10 −

irina1246 [14]

<u>Answer:</u> To calculate the pH of the buffer composed of $H_2PO_4^-\text{ and }HPO_4^{-2}$ , we use the $K_a2$

<u>Explanation:</u>

Phosphoric acid is a triprotic acid and it will undergo three dissociation reaction each having their respective dissociation constants.

The chemical equation for the first dissociation reaction follows:

$H_3PO_4\rightleftharpoons H_2PO_4^-+H^+;K_a1=6.9\times 10^{-3}$

The chemical equation for the second dissociation reaction follows:

$H_2PO_4^-\rightleftharpoons HPO_4^{2-}+H^+;K_a2=6.2\times 10^{-8}$

The chemical equation for the third dissociation reaction follows:

$HPO_4^{2-}\rightleftharpoons PO_4^{3-}+H^+;K_a3=4.8\times 10^{-13}$

To form a buffer composed of $H_2PO_4^-\text{ and }HPO_4^{-2}$ , we use the $K_a$ of second dissociation process

To calculate the $pK_a$ , we use the equation:

$pK_a=-\log (K_a)\\\\pK_a=-\log(6.2\times 10^{-8})\\\\pK_a=7.21$

To calculate the pH of buffer, we use the equation given by Henderson Hasselbalch:

$pH=pK_a2+\log(\frac{[\text{conjugate base}]}{[\text{weak acid}]})$

$pH=pK_a2+\log(\frac{[HPO_4^{2-}]}{[H_2PO_4^-]})$

We are given:

$pK_a2$ = negative logarithm of second acid dissociation constant of phosphoric acid = 7.21

$[HPO_4^{2-}]$ = concentration of conjugate base

$[H_2PO_4^{-}]$ = concentration of weak acid

Hence, to calculate the pH of the buffer composed of $H_2PO_4^-\text{ and }HPO_4^{-2}$ , we use the $K_a2$

3 0

4 years ago

Samuel adds a teaspoon of salt to a glass of water. He notices that the salt disappears. Samuel takes a sip to discover that the

Vera_Pavlovna [14]

Answer:

B

Explanation:

B It’s a physical change because the water and the salt kept their original properties.

4 0

3 years ago

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