5 The atoms of a certain element each contain 36 protons and 8 valence electrons. Which

Name two factors that influence the viscosity of a lava flow

mr_godi [17]

Three factors that affect magma viscosity are temperature, composition, and presence of dissolved gases.

6 0

3 years ago

Which statement is true about the elements in the periodic table?

aleksandr82 [10.1K]

The correct answer is elements in family 7 have similar properties because elements in the same group or family have the same number of valence electrons.

4 0

3 years ago

Read 2 more answers

Calculate the vapor pressure (in torr) at 298 K in a solution prepared by dissolving 42.4 g of the non-volatile non-electrolye u

timofeeve [1]

Answer:

The vapor pressure at 298 K for this solution is 50,49 Torr.

Explanation:

We have to apply Raoult's law to solve this which its formula is:

P pure sv° - P sl = P pure sv° . X (molar fraction)

ΔP = P pure sv° . X (molar fraction)

58,9 Torr - P sl = 58,9 Torr . X

Molar mass urea CO(NH2)2: 60,06 g/m

Molar mass ethanol: 46,07 g/m

Moles for urea: 42,4 g / 60,06 g/m = 0,705 moles

Moles for ethanol: 195 g / 46,06 g/m = 4,233 moles

X (molar fraction): moles from solute / moles from solute + moles from solvent

X (molar fraction): 0,705 / 0,705 + 4,233 = 0,142

58,9 Torr - P sl = 58.9 Torr . 0,142

58,9 Torr - 8,40 Torr = P sl

50,49 Torr = P sl

8 0

3 years ago

Classify the following substances as a Bronsted-Lowry acid, Bronsted-Lowry base, Lewis acid, and/or Lewis base.A. HCl, BF_3,B. C

ZanzabumX [31]

Answer:

A. HCl -> Bronsted-Lowry acid, BF3 -> Lewis acid

B. CCl3 -> Lewis acid, -HC -> Lewis acid or Bronsted-Lowry acid

C. H2O -> Bronsted-Lowry acid or Bronsted-Lowry base, CH3Cl -> Lewis base

D.-OCH3 -> Lewis base, NH3 -> Bronsted-Lowry acid or Lewis base.

Explanation:

For the Bronsted-Lowry theory, acids are the substances that can donate a proton H+ and bases are the substances that can receive a pronto H+.

For the Lewis theory, acid is the substance that can gain a pair of electrons, and the base is the substances that can donate the pair of electrons.

A. HCl -> The substance has a proton (H+) and it can donate it, so it's a Bronsted-Lowry acid. BF3 -> The boron (B), still has space in its shells to receive a pair of electrons, so it's a Lewis acid.

B. CCl3 -> The carbon didn't make all the bonds it can do (4), so it still can receive electrons, thus it's a Lewis acid. -HC-> It can lose the proton (H+) as a Bronsted-Lowry acid, os gains a pair of electrons at the carbon, as a Lewis acid.

C. H2O -> It can gain a proton and forms the ion H3O+, or it can lose a proton and form the ion OH-, so it can be a Brosted-Lowy acid or a Bronsted-Lowry base. CH3Cl -> It can donate pair of electrons (the hydrogen is to attached to the carbon, so it will not be lost), so it works as a Lewis base.

D. -OCH3 -> The oxygen still has pairs of electrons, which it can donate, so it's a Lewis base. NH3 -> It can gain a proton and forms the ion NH4+, so it'll be a Bronsted-Lowry acid, but the nitrogen still has electrons, which it can donate, working as a Lewis base.

6 0

3 years ago

Write a balanced chemical equation for the standard formation reaction of gaseous formaldehyde CH2O

Ymorist [56]

From the combustion of octane, the formaldehyde will be formed as this equation:

C8H18 + O2 → CH2O + H2O this is the original equation but it is not a balanced equation, so let's start to balance it:

the equation to be balanced so the number of atoms on the right side of the equation sholud be equal with the number of atoms on the lef side.

-we have 8 C atoms on left side and 1 atom on the right side so we will try putting 8 CH2O on the right side instead of CH2O

C8H18 + O2 → 8 CH2O + H2O

we have 2 O atoms on the left side and 9 atoms on the right side so we will try first to put 9 O2 instead of O2 on the left side and put 2H2O on the right side and put 16 CH2O instead of 8 CH2O to make the atoms of O are equal on both sides = 18 atoms

C8H18 + 9 O2 → 16 CH2O + 2H2O

put now we have 8 atom C on the left side and 16 atom on the right side so, we will put 2 C8H18 instead of C8H18 now we get this equation:

2C8H18 + 9O2 →16 CH2O + 2H2O

-now we have 36 of H atoms on both sides.

- and 16 of C atoms on both sides.

- and 18 of O atoms on both sides.

now all the number of atoms of O & C & H are equal on both sides

∴ 2C8H18 + 9O2 → 16 CH2O + 2 H2O

is the final balanced equation for the formation of formaldehayde

8 0

4 years ago