All categories

3 years ago

Please help

Chemistry

1 answer:

sergey [27]3 years ago

7 0

Answer:

The scientific method is an empirical method of acquiring knowledge that has characterized the development of science since at least the 17th century.

The basic steps of the scientific method are:

1) investigation

2) hypothesis

3) interpretation

4) conclusions

You might be interested in

Q15. Natural gas burns in air to form carbon dioxide and water to releasing heat. CHA(g) O2 (g) CO2 g) H20 (g) AH 802.3 kJ What

mestny [16]

Answer:

a) 0.115 g

Explanation:

The balanced reaction is:

CH₄(g) + 2O₂(g) → CO₂(g) + 2H₂O(g)

To heat 55g of water, the energy in form of heat necessary can be calculated by:

Q = mcΔT

where Q is the heat, m is the mass, c is the specific heat (for water, c = 4.18 J/gºC), and ΔT is the variation of the temperature, which is 25ºC, so:

Q = 55x4.18x25

Q = 5747.5 J = 5.7475 kJ

So, for the reaction, 1 mol of CH₄ releases 802.3 kJ, so to release 5.7475 kJ will be necessary:

1 mol ---------------- 802.3 kJ

x ---------------- 5.7475 kJ

By a simple direct three rule:

802.3x = 5.7475

x = 7.164x10⁻³mol

The molar mass of CH₄ is : 12 (of C) + 4x1 (of H) = 16 g/mol

The mass is equal to the number of moles multiplied by molar mass, the:

m = 7.164x10⁻³x16

m = 0.115 g

6 0

4 years ago

A 12.82 g sample of a compound contains 4.09 g potassium (K), 3.71 g chlorine (Cl), and oxygen (O). Calculate the empirical form

Rina8888 [55]

The empirical formula of the compound is calculated as follows

first calculate the mass of oxygen= 12-(4.09 +3.71)= 5.02g

then calculate the moles of each element, moles = mass/ molar mass

moles of K = 4.09g/39 g/mol(molar mass of K) = 0.105 moles
moles of Cl = 3.71g/35.5 g/mol(molar mass of Cl) = 0.105 moles
moles of O = 5.02g/ 16g/mol(molar mass of O) = 0.314 moles

then calculate e mole ratio by dividing each mole by the smallest number of moles ( 0.105 moles)

K=0.105/0.105= 1
Cl=0.105 /0.105=1
O= 0.314/0.105=3

therefore the empirical formula = KClO3

7 0

3 years ago

Consider the following reaction at a high temperature. Br2(g) ⇆ 2Br(g) When 1.35 moles of Br2 are put in a 0.780−L flask, 3.60 p

UNO [17]

Answer : The equilibrium constant $K_c$ for the reaction is, 0.1133

Explanation :

First we have to calculate the concentration of $Br_2$ .

$\text{Concentration of }Br_2=\frac{\text{Moles of }Br_2}{\text{Volume of solution}}$

$\text{Concentration of }Br_2=\frac{1.35moles}{0.780L}=1.731M$

Now we have to calculate the dissociated concentration of $Br_2$ .

The balanced equilibrium reaction is,

$Br_2(g)\rightleftharpoons 2Br(aq)$

Initial conc. 1.731 M 0

At eqm. conc. (1.731-x) (2x) M

As we are given,

The percent of dissociation of $Br_2$ = $\alpha$ = 1.2 %

So, the dissociate concentration of $Br_2$ = $C\alpha=1.731M\times \frac{1.2}{100}=0.2077M$

The value of x = 0.2077 M

Now we have to calculate the concentration of $Br_2\text{ and }Br$ at equilibrium.

Concentration of $Br_2$ = 1.731 - x = 1.731 - 0.2077 = 1.5233 M

Concentration of $Br$ = 2x = 2 × 0.2077 = 0.4154 M

Now we have to calculate the equilibrium constant for the reaction.

The expression of equilibrium constant for the reaction will be :

$K_c=\frac{[Br]^2}{[Br_2]}$

Now put all the values in this expression, we get :

$K_c=\frac{(0.4154)^2}{1.5233}=0.1133$

Therefore, the equilibrium constant $K_c$ for the reaction is, 0.1133

7 0

3 years ago

What are 3 sentences about the history of Egypt? Thank you for taking aside time to answer this. Please answer this as quickly a

Nataly_w [17]

1) The history of egypt is still unclear; artifacts, how the pyramids were built, gods and whatnot.
2) Egypt's history being uncovered in regards to curses and amulets is still being practiced in the country and some others because of the great influence it had.
3) Egyptians being able to construct such grand structures that still stand (pyramids) serves as evidence that proves Egypt was a very advanced civilization at the peak of their advancement.

5 0

3 years ago

BRAINLIESTTT ASAP!! PLEASE HELP ME :))

goldenfox [79]

Answer:

Solar panels and solar cells.

Explanation:

The word "solar" means "relating to or denoting energy derived from the sun's rays".

Hope this helps! :)

5 0

4 years ago

Read 2 more answers