All categories

3 years ago

Which of the following sets represents a pair of isotopes?

1 answer:

5 0

The correct option is A,
Isotopes are atoms of an element, which have the same number of protons but different number of neutrons in the nucleus of the atom. Thus, isotopes have the same atomic number but different mass number.
Looking at the options given above, you will discover that Chlorine which is given in option A is correct. Both type of chlorine has the same atomic number, which is 17, but they have different atomic masses, the atomic mass of the first one is 35 while that of the second one is 37.

You might be interested in

Based on your answer in part B, arrange the five elements in order of their reactivity. Drag the most reactive element to the to

amm1812

Answer: Order of the elements from most reactive to least reactive is:

Mg > Zn > Fe > H > Cu

Explanation: Reactivity of the elements is the tendency of the elements to loose or gain electrons with ease.

As, all the given elements are metals, so the metals which will loose electrons easily will be more reactive. To study the reactivity of metals, we use reactivity series.

The metals which are more reactive are placed on the top of the reactivity series and which are less reactive are placed at the bottom.

Hence, the order of the elements from most reactive to least reactive is:

Mg > Zn > Fe > H > Cu

Reactivity series is attached below.

6 0

3 years ago

1 Define Soft water and Hard water.

madreJ [45]

Answer

software is a set of instruction given to a computer to perform specific function. MS office etc.

the tangible parts of a computer are known as hardware.

Explanation:

software pprforms the function while hardwares are the structural parts of a computer.

3 0

2 years ago

A sample of g of pure aluminum metal is added to mL of M hydrochloric acid. The volume of hydrogen gas produced at standard temp

MArishka [77]

Answer:

V = 11.2L are produced

Explanation:

... Sample of 27g of pure aluminium, 3added to 333 mL of 3.0 M HCl..

Based on the chemical reaction:

2Al(s) + 6HCl(aq) → 2AlC₃(aq) + 3H₂(g)

Where 3 moles of hydrogen are produced when 6 moles of hydrochloric acid reacts with 2 moles of Al.

To solve this question, we need to determine limiting reactant converting each reactant to moles. With limiting reactant and the chemical reaction we can find moles of hydrogen and its volume at STP (T=273.15K; P=1atm), thus:

Moles Al-Molar mass: 26.98g/mol-:

27g * (1mol / 26.98g) = 1mol of Al

Moles HCl:

333mL = 0.333L * (3mol/L) = 1mol HCl

For a complete reaction of 1 mole of HCl are required:

1mol HCl * (2mol Al / 6mol HCl) = 0.333 moles of Al. As there is 1 mole of Al, Al is in excess and HCl is limiting reactant.

Moles of Hydrogen produced are:

1mol HCl * (3 moles H₂ / 6 mol HCl) = 0.5moles H₂ are produced.

Using ideal gas law:

PV = nRT

V = nRT/P

Where V is volume

n are moles: 0.5mol

R is gas constant: 0.082atmL/molK

T is absolute temperature: 273.15K

P is pressure: 1atm.

Solving for V:

V = 0.5mol*0.082atmL/molK*273.15K / 1atm

<h3>V = 11.2L are produced</h3>

3 0

2 years ago

For the Bradford assay, the instructor will make a Bradford reagent dye by mixing 50 ml of 95% v/v ethanol with 100 mg of Coomas

Flauer [41]

Answer:

4.25% is the final concentration of phosphoric acid.

Explanation:

Initial concentration of phosphoric acid = $C_1=85\%=0.85$

Initial volume of phosphoric acid = $V_1=50 mL$

Final concentration of phosphoric acid = $C_2=?$

Final volume of phosphoric acid = $V_2=1 L=1000 mL$

( 1L = 1000 mL)

$C_1V_1=C_2V_2$

$C_2=\frac{C_1times V_1}{V_2}$

$=\frac{0.85\times 50 mL}{1000 mL}=0.0425=4.25%$

4.25% is the final concentration of phosphoric acid.

4 0

2 years ago

Ce presiune au 40L gaz la temperatura de 100⁰C, dacă la presiunea de 6 atm și temperatura de 50⁰C volumul ocupat este de 20L.

sammy [17]

Answer:

3,46 atm

Explanation:

Tenemos;

P1 =?

T1 = 100 + 273 = 373 K

V1 = 40 litros

P2 = 6 atmósferas

T2 = 50 + 273 = 323 K

V2 = 20 litros

Desde;

P1V1 / T1 = P2V2 / T2

P1V1T2 = P2V2T1

P1 = P2V2T1 / V1T2

P1 = 6 * 20 * 373/40 * 323

P1 = 44760/12920

P1 = 3,46 atm

5 0

3 years ago