What is h+ concentrate in a solution with a pH of 1.25 round to nearest hundredth

Researchers are investigating processes that happen during digestion. Which answer choice describes only a physical change durin

ElenaW [278]

The correct answer is B. Chewing in the mouth breaks food into small pieces.

Explanation:

In physical changes, substances do not change their chemical composition or properties but only physical features such as this. This occurs during the chewing because the action of chewing only makes food to be broken down in smaller pieces but does not change its identity, composition, or properties. This does not occur once the food is in contact with saliva, the acid in the stomach, etc. because in these cases, the food reacts with other substances and a chemical reaction occurs, which changes food's identity and composition.

8 0

3 years ago

The alkali metals play virtually the same general chemical role in all their reactions. (b) How is it based on atomic properties

vfiekz [6]

b) It is based on atomic properties as alkali metals requires 7 more electrons to complete their outer orbit. And they try to give those electrons to other elements to obtain noble gas configuration.

Noble gases are the gases which do not react easily with anything. They are also called as Inert gases, and belongs to group 18 of the periodic table.

Alkali metals are the substances which are found in Group I of a periodic table. Mostly the elements which are present are:

Lithium (Li)

Sodium (Na)

Potassium (K)

Rubidium (Rb)

Cesium (Cs)

Francium (Fr)

Properties of alkali metals are: Soft, shiny reactive metals. They are soft enough to cut with knife. Metals react with water and air quickly and gets tarnish, so pure metals are stored in container by dipping them in oil to prevent oxidation.

To know more about Alkali metals, refer to this link:

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6 0

2 years ago

How much energy is required to vaporize 48.7 g of dichloromethane (CH2Cl2) at its boiling point, if its ΔHvap is 31.6 kJ/mol?

BartSMP [9]

Answer:

The answer is 18.12KJ is required to vaporise 48.7 g of dichloromethane at its boiling point

Explanation:

To solve the above question we have the given variable as follows

ΔHvap = heat of vaporisation of dichloromethane per mole = 31.6KJ/mole

However since the heat of vaporisation is the heat to vaporise one mole of dichloromethane, then, for 48.7 grams of dichloromethane, we have.

The number of moles of dichloromethane present = 48.7/84.93 = 0.573 moles

Therefore, the amount of heat required to vaporise 48.7 grams of dichloromethane at its boiling point is 31.6KJ/mole×0.573moles =18.12KJ

3 0

4 years ago

Phosphine, an extremely poisonous and highly reactive gas, will react with oxygen to form tetraphosphorus decoxide and water, as

erica [24]

<u>Answer:</u> The amount of $P_4O_{10}$ formed is 469.8 grams.

<u>Explanation:</u>

To calculate the number of moles, we use the equation:

$\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}$ ......(1)

Given mass of phosphine = 225 g

Molar mass of phosphine = 34 g/mol

Putting values in equation 1, we get:

$\text{Moles of phosphine}=\frac{225g}{34g/mol}=6.62mol$

The given chemical reaction follows:

$4PH_3(g)+8O_2(g)\rightarrow P_4O_{10}(s)+6H_2O(g)$

Assuming that oxygen gas is present in excess, it is considered as an excess reagent.

Phosphine is considered as a limiting reagent because it limits the formation of product.

By Stoichiometry of the reaction:

4 moles of phosphine produces 1 mole of $P_4O_{10}$

So, 6.62 moles of phosphine will produce = $\frac{1}{4}\times 6.62=1.655mol$ of $P_4O_{10}$

Now, calculating the mass of $P_4O_{10}$ by using equation 1:

Molar mass of $P_4O_{10}$ = 283.9 g/mol

Moles of $P_4O_{10}$ = 1.655 moles

Putting values in equation 1, we get:

$1.655mol=\frac{\text{Mass of }P_4O_{10}}{283.9g/mol}\\\\\text{Mass of }P_4O_{10}=(1.655mol\times 283.9g/mol)=469.8g$

Hence, the amount of $P_4O_{10}$ formed is 469.8 grams.

8 0

3 years ago

What is the role of gluons?

igor_vitrenko [27]

The role of the gluons is to bind together the quarks that make up protons and neutrons. That is option D.

<h3>What are gluons?</h3>

Gluons are those particles found within an atom that are responsible for binding protons and neutrons together inside the nucleus of an atom.

The gluons are capable of binding the protons and neutrons together by holding together the quarks that makes up protons and neutrons.

These gluons are known to carry a color-anticolor charge which makes up the 9 types of gluons which include:

red anti-red,

red anti-blue,

red anti-green,

blue anti-red,

blue anti-blue,

blue anti-green,

green anti-red,

green anti-blue, and

green anti-green.

An atom is the smallest indivisible part of an element that can take part in a chemical reaction.

The proton is the positive particle of an atom which is found within the nucleus.

The neutron is the particle that is found in the nucleus of an atom which doesn't have any charge.

Learn more about atom here:

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8 0

2 years ago