A compound contains 34.5% calcium, 24.1% silicon and 41.4% oxygen by mass. What is its empirical formula?

Answer:

To separate an insoluble solid from a soluble solid:  Mixing the mixture with water, filtering out the insoluble solid, and then evaporating the water to isolate the soluble solid.

Explanation:

Answer:

If you look at yourself in the front of the spoon, you see that the mirror forms an inverted real image.

Explanation:

The word 'concave' means to bend inwards.

A curved mirror is a mirror that has a curved reflecting surface.

The front side of the spoon is just like a concave mirror. If you look at yourself in the front of the spoon, you see that the mirror forms an inverted real image.

Concave mirrors produce real inverted image of an object only if it is placed further away from the mirror than the focal point.

Answer:

It shows me upside down like a ghost. OoooOooh

Explanation:

Boo

Answer:

Sulfur?

Explanation:

Sulfur has 6 valence electrons and does not have luster.

Answer:

  presents longitude lines as parallel

Explanation:

The Mercator projection shows longitude lines as  parallel, hence greatly distorts sizes and distances near the poles. A useful feature is that a course of constant bearing shows as a straight line.

Answer:

C.) presents longitude lines as parallel

Explanation:

Took it on E2020

Answer: H2 + MgCl2

Explanation: As they are on the right side of the equation/ are the products being made as a result of the reaction, they are the products.

Answer:

Milk of Magnesia would consume the most stomach acid at almost 3 times the amount as baking soda.

Explanation:

Baking Soda = NaHCO3(s)+HCl(aq)=H20(l)+CO2(g)

NaHCO3 Molar mass of 84.007 g/mol

0.012 Moles of NaHCO3 and since an equal ratio of HCl is required

we therefore neutralize 0.012 Moles of HCl

Milk of magnesia = Mg(OH)2(s)+2HCl(aq)=2H20(l)+MgCl2(aq)

Mg(OH)2(s) Molar mass: 58.3197 g/mol

0.017 Moles of Mg(OH)2 and the ratio is 2:1, so 2 moles for each 1 mole of Mg(OH)2, so we need 0.034 Moles of HCl

Answer:

The answer is Observation 1 is a result of copper atoms losing two electrons.

Explanation:

The electrons result in the color change of the copper strip, causing the gray particles to join onto the metal.

Answer:

C

Explanation:

Observation 1 is a result of the copper atoms losing two electrons. It came out as the right answer.

Answer:

wavelength = 6 cm .

Explanation:

frequency given = 5 x 10⁹ .

wavelength = velocity of light / frequency

= 3 x 10⁸ / 5 x 10⁹

= .06 m

= 6 cm

Answer:

THE SPECIFIC HEAT OF IRON IS 0.714 J/g °C

Explanation:

Heat  absorbed = 1000 J

Mass of the piece of iron = 14 g

Temeperature changes = ( 125-25)°C= 100°C

specific heat of iron = unknown

To find the specific heat of iron in the question use the formula of heat

Heat = mass * specific heat * temperature change

Specific heat = Heat / mass * temperature change

Specific heat = 1000 / 14 * 100

Specific heat = 1000 / 1400

Specific heat = 0.714 J/g °C

So therefore, the specific heat of iron is 0.714 J/g °C

Answer:

One of the most common ways of producing UV light is passing an electric current through vaporized mercury or some other gas. This type of lamp is commonly used in tanning booths and for disinfecting surfaces. The lamps are also used in black lights that cause fluorescent paints and dyes to glow.Explanation:

Answer:

The final temperature of the mixture is 44.9°C

Explanation:

Mass of the substance (gold) = 2.575g

Specific heat capacity of gold = 0.129J/g°C

Initial temperature (T1) = 75°C

Final temperature (T2) = ?

Energy lost = 10J

Heat energy(Q) = MC∇T

Q = heat energy (in this case lost)

M = mass of the substance

C = specific heat capacity of the substance

∇T = change in temperature of the substance = (T2 - T1)

Q = MC∇T

Q = MC(T2 - T1)

-10 = 2.575 × 0.129 × (T2 - 75) energy is -ve because it was energy lost.

-10 = 0.3321 × (T2 - 75)

-10 = 0.3321T2 - 24.9075

Collect like terms

0.3321T2 = 24.9075 - 10

0.3321T2 = 14.9075

T2 = 14.9075 / 0.3321

T2 = 44.88

T2 = 44.9°C

The final temperature of the mixture is 44.9°C

Answer:

A lower pH of the mouth creates bad bacteria that eventually lead to decay of the tooth.  

It can be prevented by avoiding food that causes acidity.

Explanation:

Tooth decay is caused by the pH level in the mouth dropping below 5.5, meaning it is acidic. It can be prevented by brushing your teeth as toothpaste is an alkali which will neutralise the pH level in your mouth.

Hope this helps

Answer:

Explanation:es porque las especies con nichos idénticos tienen las mismas necesidades, lo que significa que competirían exactamente por los mismos recursos.

Answer:

The correct answer to the following question will be Option C.

Explanation:

So that Option C will be the right answer.

Answer:

C.

Explanation:

Butane (C4H10) has 3 C-C bonds in the carbon chain and 10 C-H bonds

Butane ([tex]C_4H_10[/tex]) has 3 C-C bonds in the carbon chain and 10 C-H bonds

Alkanes are saturated hydrocarbons. This means that their carbon atoms are joined to each other by single bonds.

Based on the diagram, butane is considered to be an alkane. It not only contains single covalent bonds, but also has carbon and hydrogen atoms present in its structure.

When comparing both structures to one another, isobutane is a branched chain, while butane is a linear chain.

Learn more about alkane here:

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Answer: The difference between rapid combustion and spontaneous combustion...

Explanation:

Rapid combustion is a form of combustion, otherwise known as a fire, in which large amounts of heat and light energy are released, which often results in a flame.Whereas spontaneous combustion is the ignition of organic matter (e.g. hay or coal) without apparent cause, typically through heat generated internally by rapid oxidation.

Answer:

people are mostly exposed to chemicals through their nose, mouth, eyes, and ears

Explanation:

they are the easiest way for anything, bad or good, to enter the body because  people touch their face alot.

This might not answer what you were looking for but the other answer covered it pretty well so I thought I'd give you another angle to the question!

Hope this helps!!

Answer:

a) 64.27%

b) 58%

c) ethanol is the limiting reactant

d) ethanol is the limiting reactant

Explanation:

We have to note that the expected yield is the theoretical yield while the actual mass or amount of product formed is the actual yield.

a) theoretical yield=68.3g

Actual yield= 43.9 g

Percentage yield= 43.9/68.3 ×100

Percentage yield= 64.27%

b) theoretical yield= 0.0722 moles

Actual yield = 0.0419

Percentage yield= 0.0419/0.0722 × 100

Percentage yield= 58%

c) note that the limiting reactant yields the least number of moles of product

Ethanol will be the limiting reactant since it is not present in excess.

d) from the reaction equation;

1 mole of acetic acid produces 1 mole of ethyl acetate

0.58 moles of ethanol produces 0.58 moles of ethyl acetate

1 mole of acetic acid yields 1 mole of ethyl acetate

Hence 0.82 moles of acetic acid yields 0.82 moles of ethyl acetate

Hence ethanol is the limiting reactant.

Answer:

255.5cm³

Explanation:

A solution that is 38.08 % by weight has 38.08g of sulfuric acid per 100g of total solution. Thus, mass of solution you need to obtain 125g is:

125g H₂SO₄ × (100g solution / 38.08g H₂SO₄) = 328.3g of solution

As density of the solution is 1.285g / cm³, the volume of 328.3g is:

328.3g × (1cm³ / 1.285g) = 255.5cm³

Answer:

Explanation:

V1/T1 =V2/T2    at constnant pressure

Answer:

c

Explanation:

Answer:

[tex]\large \boxed{\text{-92 $^{\circ}$C}}[/tex]

Explanation:

We can use the Ideal Gas Law and solve for T.

pV = nRT

Data  

p = 1.25 atm

V = 25.0 L

n = 2.10 mol

R = 0.082 06 L·atm·K⁻¹mol⁻¹

Calculations

1. Temperature in kelvins

[tex]\begin{array} {rcl}pV & = & nRT\\\text{1.25 atm} \times \text{25.0 L} & = & \rm\text{2.10 mol} \times 0.08206 \text{ L}\cdot\text{atm}\cdot\text{K}^{-1}\text{mol}^{-1} \times T\\31.25&=&0.09847T\text{ K}^{-1}\\T& = &\dfrac{31.25}{\text{0.098 47 K}^{-1}}\\\\& = &\text{181 K}\end{array}[/tex]

2. Temperature in degrees Celsius

[tex]\begin{array} {rcl}T & = & (181 - 273.15) \, ^{\circ}\text{C}\\& = & -92 \, ^{\circ}\text{C}\\\end{array}\\\text{The temperature of the gas is $\large \boxed{\mathbf{-92 \, ^{\circ}}\textbf{C}}$}[/tex]

Answer:

A. 35Cl1-

Explanation:

Chlorine needs 1 more electron to have full octet thus will take 1 electron and possess a -1 charge.

Answer:

Here's what I get  

Explanation:

The molecules of a substance attract each other.

They are also in constant motion.

Their kinetic energy increases with the temperature.

1. Solids

If the temperature is low enough, the molecules will have little kinetic energy.

They will not be able to escape the attractions of their neighbours, so they will be fixed in place in a crystalline array.

All they can do is vibrate about their position in the array.

The substance will be a solid.

2. Liquids

If the temperature is higher, the molecules will have enough kinetic energy to slide past each other, but not enough to escape the attractions of nearby molecules.

The substance will be a liquid.

3. Gases

If the temperature is high enough, the molecules will have enough kinetic energy to escape from the surface and fly off into space.

The molecules will on average so far apart that they won't feel the attractions of others.

When they do collide, they will have energy to bounce off each other rather than stick together.

The substance will be a gas.

Answer:

The new volume is 1,000ml

Explanation:

Mathematically, we know that the number of moles per ml(volume) should be constant irrespective of the increase.

Initially, we have a volume of 500 ml and number of moles of 2.5 moles

The ratio of the number of moles to the volume is 2.5/500 = 0.005 mole/ml

Now, this is expected to remain the same even if we have an increment.

let’s call the new volume x

0.005 mol/ml = 5 moles/x ml

x = 5/0.005 = 1,000 ml

Even though you asked for ONE WAY, I found some other good ways.

1. Thoroughly wash plastic soda bottles or milk jugs with warm, soapy water.

2. Store sealed containers in a dark, dry, and cool place.

3. If after six months you have not used the stored water, empty it from the containers and repeat steps 1 through 3 above.

Answer:

Explanation:

Since Lithium gives away one electron, I believe it goes to Sulfur.

Hope this helps! :)

Answer:

Li*2S

Explanation:

ed tell chem

Answer:

the second one I think...

Answer:

The answer is the first one.

Acceleration is the change of velocity

Velocity is another term for speed with direction.

Answer: Significant figures in a measurement are all measured digits, and one estimated digit

Significant figures communicate the level of precision in measurements Significant figures are an indicator of the certainty in measurements.

Explanation:

Significant figures : The figures in a number which express the value or the magnitude of a quantity to a specific degree of accuracy or precision is known as significant digits.

The significant figures of a measured quantity are defined as all the digits known with certainty and the first uncertain or estimated digit.

Rules for significant figures:

1. Digits from 1 to 9 are always significant and have infinite number of significant figures.

2. All non-zero numbers are always significant.

3. All zero’s between integers are always significant.

4. All zero’s preceding the first integers are never significant.

5. All zero’s after the decimal point are always significant.

The true statements are

Significant figures in measurement are all measured digits, and one estimated digit

Significant figures communicate the level of precision in measurements Significant figures are an indicator of the certainty in measurements.

The following information should be considered:

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Answer:

0.046 M

Explanation:

Molarity = mol solute/ L solution = 0.23 mol/ 5 L = 0.046 mol/L = 0.046 M