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Answer:

density= mass/volume

hence density of gold rock

= 386/20

=19.3 g/cc

Answer:

237.80mL

Explanation:

Molarity of a solution can be calculated using the formula;

Molarity = number of moles (n) ÷ volume (V)

However, we first need to calculate the number of moles of Cu(NO3)2 by using the formula:

moles = mass/molar mass

Molar mass of Cu(NO3)2 = 187.56 g/mol

moles = 146.59 ÷ 187.56

moles = 0.782moles

Molarity = n/V

3.28 = 0.78/V

V = 0.78/3.28

V = 0.2378L

In milliliters (mL), 0.24 litres = 0.24 × 1000

= 237.80mL

Answer:

I am not sure this one is False.

Explanation:

Answer:

False

Explanation:

This is false because the outer part of earth is cooler than the inner. For example, the inner is filled with lava, and all kinds of stuff, so this is technically saying that the outer is much cooler, It has dirt, and dirt can be cool.

Answer:

2.5385 mol

Explanation:

do a quick conversion : 1 grams gold = 0.0050770041918285 mole using ...powered by AnyClip. 1 ... 500 grams gold to mol = 2.5385 mol

Answer:

Because it might be reactive or may lose its property in liquid form..

With the dilution of phosphoric acid, its volume will increase. To avoid the transport cost the acid might not be diluted before transporting.

Food additives are the chemicals that are used in food products, that prevent food from spoiling due to bacterial growth.

Food additives are a kind of food preservative that is added to food products to prevent spoilage and retain their nutritional value for a long time. These additives inhibit microbial growth in food.

Different types of food additives are preservatives, nutrients, sweeteners, flavoring agents, antioxidants, and colorants.

Phosphoric acid acts as a preservative and prevents the growth of mold and bacteria in foods with sugary solutions. This increases the shelf life of that beverage and improves affordability.

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Answer:

[tex]27.72 g[/tex]

Explanation:

The relationship between the number of particles and the number of mole of a substance is given by the equation  N = n L ; where  N is the number of particles, n  is the number of mole, and  L  is Avogadro's constant.

Answer:

Weather affects us in a huge number of ways. Climate influences the growth of crops, thus affecting the availability and kind of food we eat. Fluctuations in weather (e.g. dry spells, wet spells) also affect crops. Weather affects what clothes we wear.

Explanation:

Answer:

ΔHr = -566kJ/mol

Explanation:

Based on Hess's law, the ΔH of a reaction is the sum of the ΔH's of products times its coefficient subtracting the ΔH of reactants. For the reaction:

2CO(g) + O2(g) → 2CO2(g)

ΔH is:

ΔHr = 2*ΔH CO2 - (2ΔH CO + ΔH O2)

As ΔH CO2 = -393.5kJ/mol; ΔH CO = -110.5kJ/mol and ΔH O2 = 0kJ/mol

ΔHr =  2*-393.5kJ/mol - (2*-110.5kJ/mol)

Answer: more explaintion

Explanation:

Answer:

12.8 moles

Explanation:

The formula for water is H2O, so for every mole of water, there are two moles of hydrogen and one mole of oxygen.

As the ratio of oxygen particles to water particles is one to one, 12.8 moles of oxygen are required to produce 12.8 moles of water.

Therefore, 12.8 moles of water are produced from 12.8 moles of oxygen (assuming hydrogen is available in excess).

Answer:

14.7 g of chromium

Explanation:

Answer:

The formula tells us that each mole of CaCO3 contains 3 moles of Oxygen. Then 3 moles of CaCO3 would contain 3 X 3 or 9 moles of Oxygen. I mole is define as avogadro’s number of units. Avogadro’s number is 6.02 X 10^23. so the answer is 3 X 3 X 6.02 X 10^23. = 5.42 X 10^24

Answer: 61.98 is correct

Explanation:

Molar mass of calcium nitrate is 164  g/mole which is obtained by adding atomic weights of constituent elements.

Molar mass of a compound or a molecule is defined as the mass of the elements which are present in it.The molar mass is considered to be a bulk quantity not a molecular quantity. It is often an average of the of the masses at many instances.

The molecular mass and formula mass are used as synonym for the molar mass.It does not depend on the amount of substance which is present in the sample.It has units of gram/mole.

Molar masses of an element are given as relative atomic masses while that of compounds is the sum of relative atomic masses which are present in the compound.

Molar mass of calcium nitrate =40+[14+(16×3)]×2=164 g/mole.

Thus, the molar mass of calcium nitrate is 164 g/mole.

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Answer:

0.069 moles of glucose

Explanation:

(0.138 mol/L)(0.5 L) = 0.069 moles of glucose

Answer:

[tex]\boxed {\boxed {\sf 0.069 \ mol \ C_6H_12O_6}}[/tex]

Explanation:

Molarity is the moles per liter of a solution. It is found by dividing the moles of solute (glucose) by the liters of solution (water).

[tex]M= \frac {moles}{liters}[/tex]

We know the molarity is 0.138 M. 1 M is equal to 1 mole per liter, so we can rewrite the molarity as 0.138 moles per liter.

There are 0.5 liters of solution.

We are solving for the moles, so we can use x.

[tex]0.138 \ mol/L= \frac {x }{0.5 \ L}[/tex]

We must isolate the variable (x) to solve for the moles. It is being divided by 0.5 liters. The inverse operation of division is multiplication. Multiply both sides of the equation by 0.5 L.

[tex]0.5 \ L *0.138 \ mol/L= \frac {x }{0.5 \ L}* 0.5 \ L[/tex]

The liters on both sides cancel.

[tex]0.5 *0.138 \ mol= {x }[/tex]

[tex]0.069 \ mol =x[/tex]

[tex]0.069 \ mol \ C_6H_12O_6[/tex]

Ther are 0.069 moles of glucose in a 0.138 M solution with 0.5 liters of water.

Explanation:

acid ,HNO3

base,KOH

salt ,KNO3

Answer:

Some of these parts, called organelles, are specialized structures that perform certain tasks within the cell. ... It also provides a track-like system that directs the movement of organelles and other substances within cells. Endoplasmic reticulum (ER) This organelle helps process molecules created by the cell

Organelles perform specific tasks within the cells such as protein synthesis, energy production, etc.

Organelles are specialized structures that perform different functions in the cells. Examples of organelles include lysosome, nucleus, chloroplast, mitochondria, endoplasmic reticulum, etc.

It should be noted that every cell process is done in a particular location in the cell. Some of the functions that are performed by the organelle include processing of food and waste, protein synthesis, energy production, replication, etc.

For example, the nucleus is used for the storage of DNA, mitochondria is vital for energy production, the ribosome is necessary for protein synthesis, etc.

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Answer:

133.85 K

Explanation:

Initial pressure, P₁ = 635 torr

Initial temperature, T₁ = 67.0°C = 340 K

Final pressure, P₂ = 250 torr

We need to find the new temperature. The relation between temperature and pressure is given by :

[tex]\dfrac{P_1}{T_1}=\dfrac{P_2}{T_2}\\\\T_2=\dfrac{P_2T_1}{P_1}\\\\T_2=\dfrac{250\times 340}{635}\\\\T_2=133.85\ K[/tex]

So, the new temperature is equal to 133.85 K.

the are 18.01528 grams

.....

Answer:

[tex]\boxed {\boxed {\sf N_2}}[/tex]

Explanation:

Let's examine this reaction, especially the coefficients.

[tex]N_2+3H_2 \rightarrow 2NH_3[/tex]

First of all, remember that reactants are used to make the product. They are found on the left of the arrow usually. Therefore, N₂ and H₂ are the reactants, while NH₃ is the product. We can automatically eliminate NH₃ from our answer choices, because it is simply not a reactant.

Next, look at the coefficients.

Therefore, for the reaction to work, there must be 1 mole of N₂ and 3 moles of H₂.

We have 3.2 moles of N₂ and 5.4 moles of H₂.

Divide each amount given by the required amount for completion.

Therefore, there is enough nitrogen to complete the reaction 3.2 times, but only enough hydrogen for 1.8 times. If everything is completely reacted, we will run out of hydrogen and have excess nitrogen.

Answer:

Because of the electronegativity difference C-O (covalent) and Ca-O (ionic) bonds have.

Explanation:

Hello there!

In this case, in order to understand the polarity of this compound, calcium carbonate, it firstly necessary that it is comes from the definition of electronegativity, as a property defining the capacity to attract electrons from another atom; thus, since the electronegativities of calcium, carbon an oxygen are 1.0, 2.55 and 3.44, it is possible to realize this compound has O-Ca and O-C bonds according to its Lewis dot structure. In such a way, we calculate the difference electronegativity for these two bonds:

[tex]\Delta E_{O-Ca}=3.44-1.0 = 2.44\\\\\Delta E_{O-C}=3.44-2.55=0.89[/tex]

Thus, since 2.44 accounts for an ionic bond and 0.89 for a covalent one, we bear out the given statement in the question.

Answer:

a. pH = 2 b. pH = 3 c. pH = 1 d. Unanswerable

Explanation:

pH = -log[H+] OR pH = -log{H3O+]

                    and inversely

pOH = -log[OH-]

1. Determine what substance you are working with, (acid/base)

2. Determine whether or not that acid or base is strong or weak.

a. 1.0 x 10^-2M HCl

HCl is a strong acid, therefore it will dissociate completely into H+ and Cl- with all ions going to the H+, therefore, the concentration of HCl and concentration of H+ are going to be equal, meaning we simply take the negative logarithm of the concentration of HCl and that would equal pH

pH = -log[H+]

pH = -log(1.0x10^-2)

pH = 2

b. 1.0 x 10^-3M HNO3

HNO3 like part a, is a strong acid, therefore it would simply require you to take the negative logarithm of the concentration of the compound itself, to find its pH.

pH = -log[H+]

pH = -log(1.0 x 10^-3)

pH = 3

c. 1.0 x 10^-1M HI

Like the previous parts, HI is a strong acid

pH = -log[H+]

pH = -log(0.10)

pH = 1

d. HB isn't an element, nor is it a compound so that would be unanswerable.

Answer:

1.2 M

Explanation:

If you use the dilution equation (M1V1=M2V2), you end up with (50)(12)=(500)(M2), and when you solve for M2 you get 1.2 M.

Answer:

30.26 °C

Explanation:

From the question,

Q = cm(t₂-t₁)................ Equation 1

Where Q = Heat, c = specific heat capacity of Cu, m = mass of Cu, t₁ = Initial temperature, t₂ = Final temperature.

Given: Q = 1000 J, c = 0.39 J/g.°C, t₁ = 20°C, m = 250 g

Substitute into equation 1 and solve for t₂

1000 = 250×0.39(t₂-20)

250×0.39(t₂-20) = 1000

97.5(t₂-20) = 1000

(t₂-20) = 1000/97.6

(t₂-20) = 10.26

t₂ = 10.26+20

t₂ = 30.26 °C

. Consider a sample of oxygen gas at 27° C with a volume of 9.55L at a pressure

Answer:620 k

Explanation:

Answer:

False

Explanation:

Ionic bonds are actually strong, but unfortunately can be broken easily

Answer:

[tex]C=2.45\frac{J}{g\°C}[/tex]

Explanation:

Hello there!

In this case, since the thermodynamic definition of heat in terms of mass, specific heat and temperatures is given by:

[tex]Q=mC(T_2-T_1)[/tex]

We are to calculate the specific heat of the ethanol as shown below:

[tex]C=\frac{Q}{m(T_2-T_1)}[/tex]

Thus, by plugging it the given data we can obtain:

[tex]C=\frac{4650J}{250.0g(29.6-22.00\°C)} \\\\C=2.45\frac{J}{g\°C}[/tex]

Regards!