What is the meaning of a 'DeltaH' value of -400 kJ in a reaction?
OA.
The reaction requires 400 kJ of heat.
OB.
The reaction releases 400 kJ of heat.
OC. The products have 400 kJ of heat energy more than the reactants.
O D. The reaction will not occur.

A 5% m/v solution of dextrose is equivalent to a 2.76% w/v solution of dextrose (since 5 g/100 mL is equivalent to 2.76 g/100 mL, or 2.76%).

In a 5% m/v aqueous solution of dextrose, the concentration of dextrose is 5 grams per 100 milliliters of water (g/100 mL).Explanation:Dextrose is a type of sugar that is commonly used in intravenous (IV) solutions to provide energy to the body. The percentage concentration of dextrose in a solution can be expressed in various ways. One common way is as a percentage weight/volume (% w/v) solution, which means the number of grams of solute (dextrose) per 100 milliliters of solution. For example, a 5% w/v solution of dextrose means there are 5 grams of dextrose per 100 mL of solution.Another way to express the concentration of dextrose is as a percentage volume/volume (% v/v) solution, which means the number of milliliters of solute (dextrose) per 100 milliliters of solution. For example, a 5% v/v solution of dextrose means there are 5 mL of dextrose per 100 mL of solution. However, this method of expressing concentration is less common than % w/v.A 5% m/v solution of dextrose means the concentration is expressed as mass (grams) of solute per volume (milliliters) of solution. This is similar to % w/v, but the units of concentration are different. To convert from % m/v to % w/v, the molecular weight of the solute must be known. For dextrose, the molecular weight is 180.16 g/mol. Therefore, a 5% m/v solution of dextrose is equivalent to a 2.76% w/v solution of dextrose (since 5 g/100 mL is equivalent to 2.76 g/100 mL, or 2.76%).

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Answer:

14.25

Explanation:

95% of 15

=14.25

Freedom of expression is a fundamental right that allows individuals to express their opinions and ideas without fear of persecution. However, in a democratic society like South Africa, limitations to freedom of expression are necessary to protect citizens from harm. Here are three ways in which these limitations safeguard South Africans.

Firstly, limitations on hate speech protect citizens from discrimination and violence. South Africa has a history of racial and ethnic tensions, which makes it necessary to have laws that prevent speech that incites hatred or violence towards particular groups. This ensures that people are not discriminated against on the basis of their race, gender, or sexuality, and that they are free to express themselves without fear of reprisals.

Secondly, limitations on incitement to violence ensure that citizens are protected from physical harm. It is not acceptable for individuals to use their freedom of expression to incite others to commit acts of violence or engage in criminal activity. This ensures that citizens can go about their daily lives without fear of being targeted by violent groups or individuals.

Finally, limitations on defamation protect citizens from harm to their reputation and livelihood. While individuals have the right to express their opinions, they cannot do so at the expense of others' reputations. The limitations ensure that people cannot spread false or damaging information about others without consequence, which protects individuals from being unfairly targeted by others.

In conclusion, limitations on freedom of expression are necessary to protect citizens from harm in a democratic society like South Africa. By ensuring that hate speech, incitement to violence, and defamation are not allowed, individuals can express themselves freely without fear of being discriminated against or physically harmed.

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Nitrogenous bases refer to the building blocks of DNA and RNA molecules. They are molecules that contain nitrogen and other elements. Four nitrogenous bases are found in DNA: adenine (A), guanine (G), cytosine (C), and thymine (T).These bases are divided into two categories: purines and pyrimidines.

Purines include adenine (A) and guanine (G), which are two-ringed structures. Pyrimidines include thymine (T) and cytosine (C), which are one-ringed structures. Purines always pair with pyrimidines in DNA, resulting in a consistent diameter for the DNA helix.Nitrogenous bases play a crucial role in encoding genetic information because they are responsible for holding the information in the DNA molecule. They can bind to one another via hydrogen bonding. The number of hydrogen bonds between base pairs determines their strength, which is essential in DNA replication and protein synthesis. For example, the pairing of guanine with cytosine is stronger than the pairing of adenine with thymine. Adenine pairs with thymine, while guanine pairs with cytosine, resulting in complementary base pairing.A single strand of DNA contains four types of nitrogenous bases, and each base has a complementary base. A strand of DNA is always composed of nucleotides, which are made up of a phosphate group, a sugar, and a nitrogenous base. Therefore, the four nitrogenous bases are essential building blocks of DNA molecules.

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Answer:true

Explanation:

0.1MPa pressure would be required on the plunger to cause water to flow from left to right.

the force applied perpendicularly to an object's surface divided by the surface area over which it is applied.

The pressure exerted on the surface by a force of magnitude "F" Newton when applied perpendicularly to surface area "A" is equal to the ratio of F to A. The pressure (P) formula is as follows:

P=F/A

The pascal is the pressure unit used in SI (Pa).

A force of one newton applied across a surface area of one metre square is referred to as a pascal.

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Answer:

Explanation:

Fossil fuels got their name because they are made from dead organisms, mostly plants that didn't decay because they were squashed under water or mud with no oxygen.

Answer:

See Explanation.

Explanation:

Element Name: Neon (check a periodic table)

Atomic Number: 10 (number of protons)

Atomic Mass: 20 (number of protons + number of neutrons [electrons have negligible mass])

Protons: 10 (P in the black circle)

Electrons: 10 (number of red dots)

Neutrons: 10 (N in the black circle)

Valence Electrons: 8 (number of red dots on the outermost ring)

If you have any questions, let me know!!

Answer:

b atoms

Explanation:

everything is made up of atoms

Answer:

b

Explanation:

e2020

Answer:B

Explanation:It was correct

To find the break-even point, we need to determine the number of units at which the total cost equals the total revenue. In this case, variable costs of $81, the break-even point is at approximately 459 units.

The break-even point is the point at which the total cost equals the total revenue, resulting in zero profit or loss. To calculate the break-even point, we need to consider the fixed costs, variable costs, and revenues.

In this scenario, the fixed costs are given as $790, the revenues are $1.75 per unit for 180 units sold, and the variable costs are $81. The formula for calculating the break-even point is:

Break-even point = Fixed costs / (Selling price per unit - Variable cost per unit)

Substituting the given values, we have:

Break-even point = $790 / ($1.75 - $81/180)

Simplifying the equation, we find:

Break-even point ≈ 459 units

Therefore, the break-even point is approximately 459 units, meaning that the company needs to sell at least 459 units to cover its costs and avoid a loss.

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If 10 moles of P4S3 were used, the mass of P4O6 produced would be 2838.8 grams.

To determine the number of grams of P4O6 produced from 10 moles of P4S3, we need to use the balanced chemical equation and the molar masses of the compounds involved.The balanced equation for the reaction between P4S3 and oxygen to produce P4O6 is:

P4S3 + 8 O2 → P4O6 + 6 SO2

From the balanced equation, we can see that the molar ratio between P4S3 and P4O6 is 1:1. This means that for every 1 mole of P4S3 consumed, 1 mole of P4O6 is produced.The molar mass of P4S3 is 220.25 g/mol, and the molar mass of P4O6 is 283.88 g/mol.

To calculate the mass of P4O6 produced, we can use the following equation:

Mass of P4O6 = Moles of P4O6 × Molar mass of P4O6

Since the molar ratio between P4S3 and P4O6 is 1:1, the number of moles of P4O6 produced is also 10 moles.

Mass of P4O6 = 10 moles × 283.88 g/mol = 2838.8 grams

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Answer:

The change in smell

Explanation:

chemical reactions ccan lead to change in temperature, change in color and also change in smell

If there are three possible compounds with similar melting points to your unknown, then you would need to conduct at least three mixed melting points to determine which compound matches your unknown.

To identify the unknown compound, you would need to mix each of the possible compounds with a small amount of the unknown compound, and observe the melting point of each mixture. If the melting point of the mixture is similar to the melting point of the pure known compound, then that known compound is your unknown. If the melting point is different, then you would have to conduct mixed melting points with the other possible compounds until you find a match for your unknown. In summary, you would need to conduct mixed melting points with each of the three possible compounds to determine the identity of your unknown compound. If you only conducted one mixed melting point, it would not give you enough information to determine which compound matches your unknown. By conducting multiple mixed melting points, you can narrow down the possibilities and confidently identify the unknown compound.

To identify an unknown compound, mixed melting point analysis is an effective method. By mixing the unknown with a known compound and observing the melting point of the mixture, you can determine the identity of the unknown. If there are multiple possible compounds with similar melting points, you would need to conduct multiple mixed melting points to determine which compound matches your unknown.

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Answer:

0.609 Is the answer.

Explanation:

I hope this helped

The hazardous substance in automobile exhaust that is also present in high concentration in tobacco smoke is acrolein.

Substance that tobacco smoke and the exhaust of automobiles contains a has it is substance called acrolein in very very high concentration.

Inhaling acrolein can give rise to several breathing problems like shortness in breathing and also irritation in lungs.

Acrolein is formed when the fats are overheated apart from automobiles and tobacco a very low amount of acrolein is also found in over used cooking oil.

To reduce acrolein from the automobile exhaust lead based adsorption substances are preferred to be used in automobile exhaust.

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Answer:

amphibians

Explanation:

please mark this answer as brainliest

Answer:

31

Explanation:

Given parameters:

Mass number  = 66

 Number of electrons  = 35

Unknown:

Number of electrons

Solution:

In an atom, the number of protons and electrons are the same. In ions, there is a difference between the two numbers.

For this problem, once we can find the number of protons, it is therefore the number of electrons.

 Mass number = number of protons + number of neutrons

  Insert the parameters and solve;

     66  = number of protons + 35

    Number of protons  = 66  - 35  = 31

So the number of electrons is 31

Using water for a barometer is not practically good, as water has a very low density so to create pressure, a large volume will be required which is not cost-effective, choose mercury, for it as it has high density.

What is Barometer?

An instrument for measuring air pressure in a specific environment is a barometer. Short-term changes in the weather can be forecasted based on pressure tendencies. The surface weather analysis makes extensive use of air pressure sensors. It will assist in locating pressure systems, frontal limits, and surface troughs. It is a scientific tool that is useful for determining barometric pressure, which is the measurement of atmospheric pressure.

What is Density?

It is a mass of a substance per unit volume. d = M/V, where d is density, M is mass, and V is volume, is the formula for density.

Hence, using water for a barometer is not practically good, as water has a very low density so to create pressure, a large volume will be required which is not cost-effective, choose mercury, for it as it has a high density.

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Explanation:

which one of the following a correct way of finding current?

Answer:

the answer is the third figure from left

Answer:

Obtaining a Medical Certificate. Most pilots must have a valid medical certificate to exercise the privileges of their airman certificates. Glider and free.

Explanation:

Aviation safety relies heavily on maintenance. When it is not done correctly, it contributes to a significant proportion of aviation accidents and incidents. Some examples of maintenance errors are parts installed incorrectly, missing parts, and necessary checks not being performed.

Answer:

11.2823 grams of NH3 are produced
Explanation:

No. of moles for H2 = 22.3/22.4 = 0.9955 moles

By calculating number of moles produced of NH3, by using ratios:

N2 + 3H2 → 2NH3
1    :   3    :    2
? : 0.9955:  ?

part value = 0.9955/3 = 0.33183
No. of moles for NH3 = 2 * 0.33183 = 0.6637 moles

mass of produced NH3 (Molar mass = 17 g/mol) = 0.6637*17 = 11.2823 grams

The correct answer is: it is a chemical change, which could change some of the intensive and extensive properties of the carbon.

To answer this question, we must bear in mind that a chemical change involves the breaking of bonds in a substance and subsequent rearrangement of atoms to form a new substance.

This is why we say that in a chemical change, new substances are formed. Another name for a chemical change is a chemical reaction.

Having said that, it is clear that as graphite changes to diamond, bonds are broken and carbon atoms are rearranged.

This rearrangement of atoms leads to different intensive and extensive properties for graphite and diamond. For instance, graphite conducts electricity but diamond does not conduct electricity. Also, diamond is much denser and harder than graphite. A physical change can not lead to change in  some of the intensive and extensive properties of the carbon.

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Answer:

Because all machines lose input work to friction, one way to improve the efficiency of a machine is by reducing friction. Oil is used to reduce friction between the moving parts of car engines. The use of oil makes engines more efficient. Another machine that loses input work is a bicycle.

Explanation:

Hope this helps.

The factor which increases as the efficiency of a machine increases is: work output.

Efficiency can be defined as a ratio of work (energy) output to work (energy) input.

Mathematically, the efficiency of a machine is given by the formula:

\(Efficiency = \frac{W_O}{W_I} \times 100\)

Where:

Work can be defined as the amount of energy required to move an object from one point to another.

Hence, the work done by a machine is the product of the perpendicular force acting on the machine and the distance it covers or travels.

Ideally, the work output of a machine is highly dependent on its efficiency and as such, it is a factor which increases as the efficiency of a machine increases

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Answer:

24.68 g/cm³

Explanation:

We'll begin by calculating the volume of the marble. This can be obtained as follow:

Volume = 17 × 23 × 4

Volume = 1564 cm³

Next, we shall convert the mass of the marble (i.e 38.6 kg) to grams (g). This can be obtained as follow:

1 kg = 1000 g

Therefore,

38.6 kg = 38.6 kg × 1000 g / 1 kg

38.6 kg = 38600 g

Therefore, 38.6 kg mass of the marble slab is equivalent to 38600 g.

Finally, we shall determine the density of the marble slab as follow:

Volume = 1564 cm³

Mass = 38600 g.

Density =..?

Density = mass /volume

Density = 38600 g / 1564 cm³

Density = 24.68 g/cm³

Therefore, the density of the marble slab is 24.68 g/cm³

Answer: transporting oxygen-rich blood to the body

Explanation:

Answer:

Overall, the electric charge of the compound \({\rm NaOH}\) is \(0\).

Explanation:

Sodium hydroxide \({\rm NaOH}\) is an ionic compound. This compound is made up of a large number of sodium ions \({\rm Na^{+}}\) and hydroxide ions \({\rm OH^{-}}\).

As the superscripts suggest, each sodium ion \({\rm Na^{+}}\) carries a charge of \((+1)\) while each hydroxide ion \({\rm OH^{-}}\) carries a charge of \((-1)\).

The two types of ions are paired up at a one-to-one ratio within \({\rm NaOH}\). Charges on these ions would balance one another, such that the overall electric charge on the compound \({\rm NaOH}\!\) would be \(0\).