What is the total amount of heat required to completely melt 347 grams of ice at this melting point

A genetic mutation is always observable in an organism physical appearance True or false

ale4655 [162]

Answer:

false

Explanation:

false, only a small percentage of mutations cause genetic disorders—most have no impact on health or development. For example, some mutations alter a gene's DNA sequence but do not change the function of the protein made by the gene.

4 0

3 years ago

We have a sample of water vapor which cools from 150 °C to 125 °C. What happens to the motion of the molecules during this time

pentagon [3]

The motion of the molecules decreases.

<u>Explanation</u>:

Gases are formed when the energy in a system overcomes the attractive forces between the molecules. The gases expand to fill the space they occupy. In this way, the gas molecules interact little. In the gaseous state, the molecules move very quickly. As the temperature decreases, the amount of movement of the individual molecules also decreases.

The fast-moving particle slows down. When a particle speeds up, it has more kinetic energy. When a particle slows down, it has less kinetic energy. The particles in solid form are commonly connected through electrostatic powers. They don't get enough space to move around, therefore, their speed diminishes, they can't keep their standard speed like in the vaporous or fluid state.

5 0

3 years ago

A 100.0 mL solution containing 0.864 g of maleic acid (MW=116.072 g/mol) is titrated with 0.276 M KOH. Calculate the pH of the s

Lilit [14]

Answer:

pH = 1.32

Explanation:

H₂M + KOH ------------------------ HM⁻ + H₂O + K⁺

This problem involves a weak diprotic acid which we can solve by realizing they amount to buffer solutions. In the first deprotonation if all the acid is not consumed we will have an equilibrium of a wak acid and its weak conjugate base. Lets see:

So first calculate the moles reacted and produced:

n H₂M = 0.864 g/mol x 1 mol/ 116.072 g = 0.074 mol H₂M

54 mL x 1L / 1000 mL x 0. 0.276 moles/L = 0.015 mol KOH

it is clear that the maleic acid will not be completely consumed, hence treat it as an equilibrium problem of a buffer solution.

moles H₂M left = 0.074 - 0.015 = 0.059

moles HM⁻ produced = 0.015

Using the Henderson - Hasselbach equation to solve for pH:

ph = pKₐ + log ( HM⁻/ HA) = 1.92 + log ( 0.015 / 0.059) = 1.325

Notes: In the HH equation we used the moles of the species since the volume is the same and they will cancel out in the quotient.

For polyprotic acids the second or third deprotonation contribution to the pH when there is still unreacted acid ( Maleic in this case) unreacted.

3 0

3 years ago

A certain atom has 11 electrons 8 neutrons and a charge of -1. What is it’s atomic mass

Arlecino [84]

Answer:

20 amu

Explanation:

An atom consist of electron, protons and neutrons. Protons and neutrons are present with in nucleus while the electrons are present out side the nucleus.

All these three subatomic particles construct an atom. A neutral atom have equal number of proton and electron. In other words we can say that negative and positive charges are equal in magnitude and cancel the each other. For example if neutral atom has 6 protons than it must have 6 electrons. The sum of neutrons and protons is the mass number of an atom while the number of protons are number of electrons is the atomic number of an atom.

Atomic mass = Number of protons + number of neutrons

Atomic number = Number of electrons or number of protons.

In given question it is stated that atom has 11 electrons and -1 charge it means this atom has 12 electrons in neutral state.

Thus it has 12 protons because number of electrons and protons are always equal.

Atomic mass of given atom:

Atomic mass = Number of protons + number of neutrons

Atomic mass = 12 + 8 = 20 amu

7 0

3 years ago

What mass of lead (II) chloride is produced when 200.0 mL of a 0.250 M solution of sodium chloride is mixed with 200.0 mL of a 0

kow [346]

Answer:

Option d. 6.95 g

Explanation:

First of all, we state the reaction:

2NaCl + Pb(NO₃)₂ → PbCl₂ + 2NaNO₃

We determine the moles of each reactant, to state the limiting

Firstly we convert volume frm mL to L

0.200 L . 0.250M = 0.05 moles of NaCl

0.200L . 0.250M = 0.05 moles of Pb(NO₃)₂

Acording to stoichiometry we know that relation is 1:2, so the limiting reagent is the NaCl.

For 1 mol of Pb(NO₃)₂ I need 2 moles of NaCl

For 0.05 moles of Pb(NO₃)₂ I would need, the double → 0.1 moles

(We only have, 0.05 moles of NaCl)

Stoichiometry to the formed product is 2:1

From 2 moles of NaCl I produce 1 mol of PbCl₂

From 0.05 moles I would produce, the half → 0.025 moles

Let's convert the moles to mass → 0.025 mol . 278.1 g / 1mol = 6.95 g

8 0

3 years ago