"Seeing is believing."

What is the pH of a solution that<br> contains [H+]=3.18 x 10^-8 M?

Xelga [282]

Answer:

7.50

Explanation:

pH=-log(H3O+)

- Hope that helps! Please let me know if you need further explanation.

4 0

3 years ago

What’s molar mass? For chemistry

Alik [6]

In chemistry, the molar mass of a chemical compound is defined as the mass of a sample of that compound divided by the amount of substance in that sample, measured in moles.

3 0

3 years ago

Complete the electron-dot structure of s-allylcysteine, showing all lone-pair electrons.

erastova [34]

The structural formula of <span>s-allylcysteine is shown in the picture (top figure). To create its Lewis structure, draw all its bonds between elements. Each single bond contains two electrons. There is an octet rule that must be obeyed by most elements. Each element should be surrounded with 8 electrons. The hydrogen is exempted of this rule. So, there are 4 lone pairs for the S atom, 1 lone pair for the N atom, and 2 lone pairs each for the 2 O atoms.</span>

7 0

3 years ago

Which of the following numbers count as exact numbers and do not count when determining significant figures in a calculation? 1.

rewona [7]

Answer :

(1) Density do not count as exact number.

(2) Volume count as exact number.

(3) Length count as exact number.

(4) Speed do not count as exact number.

(5) Number count as exact number.

(6) Mass do not count as exact number.

Explanation :

Exact numbers : It is a defined or integer value which comes from counting numbers of objects.

They have an infinite number of significant figures.

For example : 12 eggs in a dozen, 1000 g in a kilogram and 2.54 cm in an inch.

Now we have to determine the following numbers count as exact numbers.

(1) Density : 3.7 g/mL

Density do not count as exact number.

(2) Volume : 1000 mL/L

Volume count as exact number.

(3) Length : 2.54 cm/in

Length count as exact number.

(4) Speed : 65.2 km/hr

Speed do not count as exact number.

(5) Number : 14 aardvarks

Number count as exact number.

(6) Mass : 38.741 g

Mass do not count as exact number.

4 0

3 years ago

Measurements show that the enthalpy of a mixture of gaseous reactants increases by 319kJ during a certain chemical reaction, whi

hram777 [196]

Answer:

the change in energy of the gas mixture during the reaction is 227Kj

Explanation:

THIS IS THE COMPLETE QUESTION BELOW

Measurements show that the enthalpy of a mixture of gaseous reactants increases by 319kJ during a certain chemical reaction, which is carried out at a constant pressure. Furthermore, by carefully monitoring the volume change it is determined that -92kJ of work is done on the mixture during the reaction. Calculate the change of energy of the gas mixture during the reaction in kJ.

From thermodynamics

ΔE= q + w

Where w= workdone on the system or by the system

q= heat added or remove

ΔE= change in the internal energy

q=+ 319kJ ( absorbed heat is + ve

w= -92kJ

If we substitute the given values,

ΔE= 319 + (-92)= 227 Kj

With the increase in enthalpy and there is absorbed heat, hence the reaction is an endothermic reaction.

8 0

3 years ago