PLEASE HELPP!!!
PLEASE HELP!!!
Write the sentences in your copybook and draw a line through one of the words in
bold to complete each of these sentences about alkali metals correctly.

 Alkali metals generally become more / less dense going down the group.

 The melting and boiling points of alkali metals increase / decrease down the group.

 The softness of alkali metals increases / decreases going down the group.

 The speed with which alkali metals react with oxygen increases / decreases going
down the group.

Explanation:

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Answer:

A 1.732 g sample of iron is heated in air. It oxidizes to form a product with a mass of 2.205 g. What is the empirical formula of the product? FeO 4. Caffeine is made of 49.48% carbon, 5.19% hydrogen, 28.85% nitrogen, and 16.48% oxygen by mass.

Explanation:

The empirical formula of the product formed by the reaction of iron and oxygen is FeO.

Let's consider the following generic chemical equation:

Fe + O₂ ⇄ FexOy

According to the law of conservation of mass, the sum of the masses of the reactants is equal to the sum of the masses of the products. The mass of O₂ that reacted, and remains in the oxide is:

[tex]mFe + mO_2 = mFexOy\\mO_2 = mFexOy - mFe = 2.205 g - 1.732 g = 0.473 g[/tex]

The oxide has 1.732 g of Fe and 0.473 g of oxygen and a total mass of 2.205 g. To determine the empirical formula, we need to calculate the percent composition.

[tex]\%Fe = \frac{mFe}{mFexOy} \times 100 \% = \frac{1.732 g}{2.205 g} \times 100 \% = 78.55\%[/tex]

[tex]\%O = \frac{mO}{mFexOy} \times 100 \% = \frac{0.473 g}{2.205 g} \times 100 \% = 21.45\%[/tex]

Now, we will divide each percentage by the atomic mass of the element.

[tex]Fe: 78.55/55.85 = 1.406\\O: 21.45/16.00 = 1.340[/tex]

Finally, we divide both numbers by the smallest one.

[tex]Fe: 1.406/1.340 \approx 1 \\O: 1.340/1.340 = 1[/tex]

The empirical formula of the product is FeO.

You can learn more about empirical formulas here: https://brainly.com/question/1363167

Answer:

69

Explanation:

I thought that I answer is correct

Answer:

The answer is 69

Explanation:

Because if you add one its 66, and so on, hope this helps! but if you add five it will be 69, if you need help with easy equations let me know

Force = The external energy that changes or tends to change the state of any body or object is called force.

Speed = The rate of distance is called speed.

Answer:

Force is a push or pull which changes or tend to change the position of a body.

The rate of change its position with time or magnitude is called speed.

Answer:

62.5 moles of O₂.

Explanation:

We'll begin by writing the balanced equation for the reaction. This is illustrated below:

2C₈H₁₈ + 25O₂ —> 16CO₂ + 18H₂O

From the balanced equation above,

2 moles of C₈H₁₈ reacted with 25 moles of O₂.

Finally, we shall determine the number of mole of O₂ needed to react with 5 moles of C₈H₁₈. This can be obtained as shown below:

From the balanced equation above,

2 moles of C₈H₁₈ reacted with 25 moles of O₂.

Therefore, 5 moles of C₈H₁₈ will react with = (5 × 25) / 2 = 62.5 moles of O₂.

Thus, 62.5 moles of O₂ is needed for the reaction.

Answer:

sodium chloride

hope that helped :)

Answer:

Chlorine is a greenish yellow gas at room temperature and atmospheric pressure. ... yielding chlorine water, and from this solution a solid hydrate of ideal ...

Solution :

Cd(s) ---------------------->  [tex]Cd^{+2}[/tex] (aq) + 2[tex]e^-[/tex]      ,     [tex]E_0[/tex]  =   0.34 v

[tex]Cu^{+2}[/tex]  (aq)  +   2[tex]e^-[/tex]  ------------> Cu (s)             ,     [tex]E_0[/tex]  =  -0.04 v

----------------------------------------------------------------------------------------------

Cd(s)  +  [tex]Cu^{+2}[/tex]  (aq)  ------------->  [tex]Cd^{+2}[/tex] (aq)  +  Cu (s)   ,      [tex]E_0[/tex]  =  0.30 v  

The cell potential is defined as the measure of [tex]\text{ potential difference }[/tex]  between the [tex]\text{two half cells}[/tex] of an electrochemical cell.  

Answer:

The composition of air can be determined by an experiment which includes passing a known volume of air, measured at a known temperature and pressure, over sufficient amount heated copper granules/powder, and measuring the volume gas remaining after the gas cools down to the temperature at which the first measurement was taken

Oxygen reacts with copper according to the following chemical reaction

2Cu (s) + O₂ (g) → 2CuO (s)

Cupper does not react with the other constituents of air

Whereby the initial volume of air was 100 cm³, we have;

Percentage of oxygen in air = 100 - The final volume reading of the container initially holding the air

When done using am appropriate experimental setup, the percentage of gases remaining equals 79% to 80%, therefore, the percentage composition of oxygen in air is between 20 and 21 percent

Explanation:

Answer:

See explanation

Explanation:

Tyndall effect refers to the scattering of light in a solution. Tyndall effect occurs when the size of particles in the solution exceeds 1 nm in diameter. Such solutions are actually called false solutions.

In tincture of iodine, the size of particles in solution is less than 1 nm in diameter hence the solution does not exhibit Tyndall effect. Hence, tincture of iodine is a true solution.

Therefore, if the size of particles in solution exceeded 1nm in diameter, Tyndall effect is observed.

Answer:

sodium bicarbonate solution

Answer:

nitrogen is used in the production of  1) fertilisers  2) nitric acid  3) nylon  4) dyes  and  5) explosives

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The scientific question related to the game of basketball is option D: "Do teams that practice more win more games?"

This question is scientific because it explores a cause-and-effect relationship between practice and game outcomes. It can be investigated through empirical observation and data analysis.

To answer this question, researchers could collect data on the practice hours of different basketball teams and compare them to their corresponding game performance. Statistical analysis could be used to determine if there is a correlation between practice time and winning percentage or other performance metrics.

By examining a large sample of teams over an extended period, researchers could draw conclusions about the impact of practice on game outcomes. This scientific inquiry would contribute to the understanding of the factors that influence team success in basketball and could potentially inform training strategies and coaching techniques.

For more question on basketball

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Answer:

the group with helium at the top

Explanation:

I just took it

Explanation:

here's the answer to your question

Answer:

[tex]\boxed {\boxed {\sf 2.36 \ mol \ SO_2}}[/tex]

Explanation:

We are asked to convert grams to moles. We will use the molar mass and dimensional analysis to perform this conversion.

The molar mass is the mass of 1 mole of a substance. These values are found on the Periodic Table because they are equivalent to the atomic masses, but the units are grams per mole instead.

We are given a mass of sulfur dioxide (SO₂). Look up the molar masses of the individual elements.

Notice that the formula of the compound contains a subscript. The subscript after O means there are 2 moles of oxygen in 1 mole of sulfur dioxide. We must multiply oxygen's molar mass before adding sulfur's.

Now we will use dimensional analysis to convert grams to moles. From the molar mass, we know there are 64.068 grams of sulfur dioxide per mole, so we can set up a ratio.

[tex]\frac {64.068 \ g \ SO_2} {1 \ mol \ SO_2}[/tex]

We are converting 151 grams to moles, so we multiply by this value.

[tex]151 \ g \ SO_2 *\frac {64.068 \ g \ SO_2} {1 \ mol \ SO_2}[/tex]

Flip the ratio so the units of grams of sulfur dioxide cancel.

[tex]151 \ g \ SO_2 *\frac {1 \ mol \ SO_2}{64.068 \ g \ SO_2}[/tex]

[tex]151 *\frac {1 \ mol \ SO_2}{64.068 }[/tex]

[tex]\frac {151}{64.068 } \ mol \ SO_2[/tex]

[tex]2.356870825 \ mol \ SO_2[/tex]

The original measurement of grams (151) has 3 significant figures, so our answer must have the same. For the number we calculated, that is the hundredth place. The 6 in the thousandth place tells us to round the 5 in the hundredth up to a 6.

[tex]2.36 \ mol \ SO_2[/tex]

151 grams of sulfur dioxide is approximately 2.36 moles of sulfur dioxide.

Answer:

Create a new account as the thing you're experiencing now is due to the fact that Brainly had blocked your account.

Explanation:

a unit of mass used to express atomic and molecular weights, equal to one twelfth of the mass of an atom of carbon-12.

Answer:

Atomic Mass Unit is also called Dalton. It is used to express atomic and molecular weight. It is defined as 1/12 of the mass of an unbound neutral atom of carbon.

Answer:

Acid is a molecule capable of donating hydrogen ion and they form aqueous solutions with a sour taste while base is a substance that accepts proton from proton donor and in aqueous solution, they have an astringent or bitter taste. Moreover, a good example for base is sodium hydrogen carbonate as baking soda or baking powder and for acid, the most common example is the acetic acid or vinegar.

Answer:

Well, for starters, bases mostly consist of soaps and cleaning products, acids consist of vinegar,lemon,and stuff like that. Most acids on the basis of touch can burn your skin or be very sour, unlike bases which are more soapy and have a cleaner touch.A good example of an acid is vinegar, which can be used for cleaning but can also be used for making foods, on the other hand. A good example of a base is dish soap. It is used for cleaning.

Explanation:

i just did the exam and got a 100

Answer:

the reactants are carbon dioxide ,iron, oxygen

Ca^2+ ion  is smaller than Mg^2+ ion hence it has a greater heat of formation or lattice energy.

When a crystal lattice is formed, the energy that is released if the component ions of the compound are brought together from infinity is called the lattice energy. It is the energy released when a crystal lattice is formed from its component ions.

The question lets us know that the heat released by the compounds depends on the energy released upon formation of the compound. Hence, the higher the energy released upon formation, the higher the magnitude of heat released upon dissolution of the compound.

Recall that lattice energy depends on the size of the ions. Thus, the smaller the ions, the higher the lattice energy.

Ca^2+ is smaller than Mg^2+ hence more energy is given off when CaCl2  is formed than when MgCl2  is formed.

As stated above, the greater the lattice energy, the greater the heat released when the lattice dissolves and the higher the rise in temperature.

Putting all these together, Sample A must be CaCl2 while sample B must be MgCl2.

https://brainly.com/question/2815368

Answer:  1)  temperature, 2) add a catalyst, and 3) concentrations

Explanation:  A rise in temperature adds kinetic energy to the reactants, leading to more frequent, and energetic collisions, which will often accelerate the reaqction.  A catalyst is an agent that helps the reaction move forward more quickly by offering a substrate that aids in orienting the reactants for more efficient reaction.  A higher concentration increases the chances of collisons that result in products.

Answer:

oxygen molecule has two oxygen atom . Each O atom share 2 electrons to form two covalent bonds out of which one is sigma bond and other is pi bond . sigma bond is formed by axial overlap 2p atomic orbitals of oxygen and pi bond is formed of lateral overlap of 2p atomic orbitals of oxygen .

Answer:

Nitrogen oxides are used in the production of nitric acid, lacquers, dyes, and other chemicals. Nitrogen oxides are used in rocket fuels, in the nitrification of organic chemicals, and in the manufacture of explosives.

Explanation:

Answer: broooo what is this

Explanation:

Explanation:

here's the answer to your question

double arrow just mean that it's a reversible process, and the reaction can go back and forth.

Answer:

Some examples of solutions are salt water, rubbing alcohol, and sugar dissolved in water. ... In our example of salt water, the solute is the salt. Solvent: this is the substance that makes up the majority of the solution. This is the part where the solute is dissolved.

Explanation:

I hope they should be right answer

Answer:

C2H4 Ethylene

Explanation:

Hope it helps! :)