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Answer:

A diamond contains 5.0 x 10 21 atoms of carbon.

Answer:

DNA

Explanation:

Genetic material DNA is passed from cell to cell.

DNA is Deoxyribonucleic acid. It is a polymer composed of two polynucleotide chains. These chains coil around each other to form a double helix. The polymer carries genetic instructions for the development, functioning, growth and reproduction of all known organisms and many viruses. It keeps on transferring from generation to generation. Two types of Nucleic acids are DNA and ribonucleic acid.

In DNA, 4 bases are present that are Adenine, Guanine, Cytosine and Thymine. Whereas Thymine is replaced by Uracil in case of RNA.

These bases are connected by hydrogen bonds with each other.

The configuration of the DNA molecule is highly stable, allowing it to act as a template for the replication of new DNA molecules, as well as for the production (transcription) of the related RNA (ribonucleic acid) molecule.

Therefore, Genetic material DNA is passed from cell to cell.

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Answer:

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The body regulates those levels in an example of homeostasis. When levels decrease, the parathyroid releases hormones. If calcium levels become too high, the thyroid helps out by fixing calcium in the bones and lowering blood calcium levels. The nervous system helps keep homeostasis in breathing patterns.

Answer:

The following is a rather lengthy discussion on chemical stoichiometry, but it will lead you through the mole concept and its application to chemical reaction stoichiometry. The problems are different than the one posted, but if you can follow this, then you can work your problem of interest.

Explanation:

Stoichiometry is very easy to master if you understand the ‘mole concept’ and how it is used to define and describe chemical process mathematically. A ‘mole’ – in chemistry – is the mass of substance containing one Avogadro’s Number of particles. That is, N₀ = 6.023 x 10²³ particles / mole. When working with chemical reactions and equations data should be first converted to moles using the following conversions.  

1 mole = 1 formula weight = 6.023 x 10²³ particles = 22.4 liters at STP(0⁰, 1atm).

In this problem you are given the equation 2Na + 2H₂O => 2NaOH + H₂. ‘Reading the equation’ there are 2 moles of Na, 2 moles of water, 2 moles of NaOH and 1 mole of H₂. In another example 3H₂ + N₂ => 2NH₃ there are 3 moles of H₂, 1 mole of N₂ and 2 moles of NH₃. The mole values can be multiples or fractions but if one mole value increases all the remaining mole values increase or decrease proportionally. For example:

Using the equation 2Na + 2H₂O => 2NaOH + H₂, one could multiply the equation by 2 giving 4Na + 4H₂O => 4NaOH + 2H₂. The equation shows balance but is not in standard form. If one multiplies the equation by ½ gives Na + H₂ => NaOH + ½H₂. Again, the equation shows balance but is not in standard form.

Standard form of equation also implies the equation conditions are at 0⁰C & 1atm pressure and 1 mole of any gas phase substance occupies 22.4 Liters volume. Such is the significance of converting given data to moles as all other substance mass (in moles) are proportional.  

1st problem, 1.76 x 10²⁴ formula units of Na will react with water (usually read as an excess) to produce (?) grams of H₂.

1st write the equation followed by listing the givens below the respective formulas… That is…

                         Na                      +            H₂O       =>    NaOH    +    H₂,

Given:      1.76 x 10²⁴ atoms                excess             ---------          ? grams

               = 1.76 x 10²⁴atoms/6.023 x 10²³atoms/mole

               = 2.922moles                                        produces  =>    2.922moles H₂ (b/c coefficients of Na & H₂ are same)

                                                      Convert moles to grams =>    2.922moles H₂  x  2.000 grams H₂/mole H₂

                                                                                                              = 5.8443 grams H₂

2nd problem, 3.5 moles Na will react with H₂O (in excess) to produce (?) moles of NaOH.

Again, write equation and assign values to each formula unit in the equation.

                         Na                      +            H₂O        =>           NaOH    +    H₂,

Given:            3.5moles                       excess                      ? grams       ----

Since coefficients of balanced std equation are equal …

                      3.5 moles Na                          produces =>     3.5 moles NaOH

                                             Convert moles to grams =>     3.5 moles NaOH x 40 g Na/mole Na

                                                                                                  = 140 grams NaOH

3rd problem, 2.75 x 10²⁵ molecules H₂O will react with (?) atoms of Na.

Same procedure, convert to moles, solve problem by ratios then convert to needed dimension at end of problem.

                         Na          +            H₂O                                   =>           NaOH           +    H₂

Given:           excess            2.75 x 10²⁵ molecules H₂O    =>      ? atoms NaOH       ----

Convert to moles =>          2.75 x 10²⁵ molecules H₂O / 6.023 x 10²³ molecules H₂O/mole H₂O  

                                             = 45.658 moles H₂O              =>  45.658 moles NaOH  (coefficients are equal)

Convert moles NaOH to grams NaOH                            =>   45.658 moles NaOH x  40 grams NaOH/mole NaOH

                                                                                                     = 1826.33 grams NaOH  

Master the mole concept and you master a lot of chemistry! Good luck.

Answer:

The answer would be 15, letter D.

Explanation:

Since it has 5 electrons in its outermost shell, it will be located in group 15 in the periodic table.

The electron configuration of an atom of an element for the electrons in the s and p orbitals 15th group number of the element in the periodic table option D is correct.

Tha common electronic configuration of 15th group elements in ns2 np3, Group 15 elements in the modern periodic table are known as the pnictogens which means suffocation in Greek language.

This group consists of nitrogen (N), phosphorus (P), arsenic (As), antimony (Sb) and bismuth (Bi).

The group 15 elements consist of five valence electrons. Due to this the elements can either lose five electrons or gain three electrons in order to attain the stable configuration. The general electronic configuration of nitrogen family is ns 2 np 3.

therefore , because of ns2 np3 option D is correct.

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Answer:

The correct answer is -

1. D. mold

2. A. Cast

3. F. trace fossil

4. C. original material fossils

5. B. fossil record.

Explanation:

Mold is the impression of an organism in a rock that occurs due to the complete dissolving of the organism and only an impression left in sedimentary rocks.

The cast is a fossil copy of an organism in a rock that takes place when water-containing minerals fill the molds and creates a three-dimension copy of the fossil.

Trace fossils are the fossils that are preserved in such a manner that records of biological activity stored only instead of remains of plants or animals.

Storing originals animals or parts of the remaining such as tissue of an organism in natural form is known as original-material fossils.

Fossil records are the fossils ever found or discovered on the earth.

Answer:

false

Explanation:

Answer:

For 1, your answer is b. absorbs, endothermic. For 2, your answer is a. a solution becomes more dilute.

Explanation:

I took the test.

Answer:

no H2O molecules are produced:)

Explanation:

Answer: 18 g of water occupies one mole and one mole contains Avagadro’s no. of molecules = 6.023*10^23 molecules .

Explanation:question says 72 g of water . 72 g of water occupies 4 moles.

So the no. of molecules in 72 g of water has 4*(6.023*10^23) molecules .

Answer:

The sun would appear to move more slowly across Mercury's sky.

Explanation:

This is because, the time it takes to do one spin or revolution on Mercury is 176 days (which is its period), whereas, the time it takes to do one spin or revolution on the Earth is 1 day.

Since the angular speed ω = 2π/T where T = period

So on  Mercury, T' = 176days = 176 days × 24 hr/day × 60 min/hr × 60 s/min = ‭15,206,400‬ s

So, ω' = 2π/T'

= 2π/15,206,400‬ s

= 4.132 × 10⁻⁷ rad/s

So on  Earth, T" = 1 day = 1 day × 24 hr/day × 60 min/hr × 60 s/min = ‭‭86,400‬ s

So, ω" = 2π/T"

= 2π/86,400‬ s

= 7.272 × 10⁻⁵ rad/s

Since ω' = 4.132 × 10⁻⁷ rad/s << ω" = 7.272 × 10⁻⁵ rad/s, the sun would appear to move more slowly across Mercury's sky.

Answer: 1. 6 x 10*6

               2. 9 x 10*3

                3. 6 x 10*1

                 4. 5.4 x 10*6

                   5. 6 x 10*0

                    6. 2 x 10*7

Explanation:

Answer:

T₂ = 478.93 K

Explanation:

Given that,

Initial pressure, P₁ = 178 kPa

Initial temperature, T₁ = 37°C = 310 K

Final pressure, P₂ = 275 kPa

We need to find the new temp of the air in the tire, assuming the volume is constant. We know that,

[tex]\dfrac{P_1}{T_1}=\dfrac{P_2}{T_2}\\\\T_2=\dfrac{P_2T_1}{P_1}\\\\T_2=\dfrac{275\times 310}{178}\\\\T_2=478.93 K[/tex]

So, the new temperature is equal to 478.93 K.

Answer:

diple doble

Explanation:

Answer:

1

Explanation:

single displacement replaces one element with another and it's product is a pure element.

Answer:

lol thanks for the 10

Explanation:

Answer:

Mineral Acid

Explanation:

Answer:

sulfuric Acid

Explanation:

Sulfuric acid, sulfuric also spelled sulphuric (H2SO4), also called oil of vitriol, or hydrogen sulfate, dense, colourless, oily, corrosive liquid; one of the most commercially important of all chemicals.

Answer:

Una cantidad de gas ocupa un volumen de 80 cm3

a una presión de 750 mm Hg. ¿Qué volumen

ocupará a una presión de 1,2 atm.si la temperatura no cambia?

Explanation:

El volumen inicial de una cierta cantidad de gas es de 200 cm3

a la temperatura de 20ºC. Calcula el

volumen a 90ºC si la presión permanece constante.

Answer:

The ice cubes gain energy

Explanation:

The ice cubes are gaining energy from the water's carbon dioxide, or H2O. They then melt because they cannot hold that energy.

Answer:

Potassium Sulfide

Explanation:

K is more reactive than Fe which means K displaces Fe from the equation

Explanation:

Hi,

I don't think it can affect humans because humans and birds don't get into contact with each other. An insect and a human do, therefore a human could be affected, but a bird doesnt.

I hope this helps :)

Answer:

La energía necesaria para calentar el bloque de aluminio es 54927 J.

Explanation:

Se denomina calorimetría a la medición y el cálculo de las cantidades de calor que intercambia un cuerpo o un sistema.

De esta manera, entre el calor y la temperatura existe una relación de proporcionalidad directa (Dos magnitudes son directamente proporcionales cuando existe una constante de manera que cuando una de las magnitudes aumenta, la otra también; y lo mismo ocurre cuando alguna de las dos disminuye.). La constante de proporcionalidad depende de la sustancia que constituye el cuerpo como de su masa, y resulta el producto del calor específico por la masa del cuerpo. Entonces, la ecuación que permite calcular intercambios de calor es:

Q=c*m*ΔT

Donde Q es el calor intercambiado por un cuerpo de masa m, constituido por una sustancia de calor específico c y donde ΔT es la variación de temperatura.

En este caso:

Reemplazando:

Q= 0.9 [tex]\frac{J}{g*C}[/tex]*850 g* 71.8  C

y resolviendo se obtiene:

Q= 54927 J

La energía necesaria para calentar el bloque de aluminio es 54927 J.

Answer: 4. We know that one mole of any chemical compound always contains 6.022 x 10^23 molecules. Therefore, we can calculate the number of molecules of 2.25 moles of sulfur dioxide SO2 by multiplying the number of moles by the Avogadro's constant 6.022 x 10^23:    

    2.25 moles SO2 (6.022x10^23 molecules/1mole) = 1.355 x 10^24 molecules of sulfur dioxide

5. The number of moles of sodium chloride are 0.40 moles

Explanation:

the balanced chemical equation was shown here :

2 K3PO4 (aq) +  3 NiBr2(aq)      ------------>>   Ni3(PO4)2 (s) +  6 KBr (aq)

The balanced chemical equation when aqueous potassium phosphate reacts with aqueous nickel(II) bromide to produce solid nickel(II) phosphate and aqueous potassium bromide is:

2 K₃PO₄(aq) + 3 NiBr₂(aq) ⇒ Ni₃(PO₄)₂ + 6  KBr(aq)

Let's consider the unbalanced chemical equation that occurs when aqueous potassium phosphate reacts with aqueous nickel(II) bromide to produce solid nickel(II) phosphate and aqueous potassium bromide.

K₃PO₄(aq) + NiBr₂(aq) ⇒ Ni₃(PO₄)₂ + KBr(aq)

We will balance it using the trial and error method.

2 K₃PO₄(aq) + 3 NiBr₂(aq) ⇒ Ni₃(PO₄)₂ + KBr(aq)

We will get the balanced equation by multiplying KBr by 6.

2 K₃PO₄(aq) + 3 NiBr₂(aq) ⇒ Ni₃(PO₄)₂ + 6  KBr(aq)

The balanced chemical equation when aqueous potassium phosphate reacts with aqueous nickel(II) bromide to produce solid nickel(II) phosphate and aqueous potassium bromide is:

2 K₃PO₄(aq) + 3 NiBr₂(aq) ⇒ Ni₃(PO₄)₂ + 6  KBr(aq)

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Answer:

Explanation:

Unit 10 - Acid/Base ... (a) Mg(OH. 2. ) (b) Mg(OH). 2. (c) Mg. 2. OH. (d) MgOH. 2. Standard: ... balanced equation for these neutralization reactions: 3. HCl + NaOH → ... H2CO3 + Ca(OH)2 → ... C5.7B Predict products of an acid-base neutralization. 8. 2 NH4OH + H2S ...An Arrhenius base is a compound that increases the OH − ion concentration in ... and a base is called a neutralization reaction and can be represented as follows: ... chemical equation for the neutralization reaction between HCl and Mg(OH) 2. ... acid, an Arrhenius base, or neither. a) NaOH. b) C 2H 5OH. c) H 3PO 4. 6

Answer: chemical element

Explanation: A chemical element is a substance that contains only one type of atom, which is the smallest particle of an element.

Answer:

C. He feels excited and happy

Explanation:

Answer:

La constante de equilibrio Ka del ácido láctico es 1.38x10⁻⁴.

Explanation:

El ácido láctico es un ácido débil cuya reacción de disociación es la siguiente:

CH₃CHOHCOOH + H₂O ⇄ CH₃CHOHCOO⁻ + H₃O⁺   (1)

0.025M - x                                        x                     x                    

La constante de acidez del ácido es:        

[tex] Ka = \frac{[CH_{3}CHOHCOOH^{-}][H_{3}O^{+}]}{[CH_{3}CHOHCOOH]} [/tex]

Sabemos que la concentración del ácido inicial es:

[CH₃CHOHCOOH] = 0.025 M    

Y que a partir del pH podemos hallar [H₃O⁺]:

[tex] pH = -log[H_{3}O^{+}] [/tex]

[tex] [H_{3}O^{+}] = 10^{-pH} = 10^{-2.75} = 1.78 \cdo 10^{-3} M [/tex]

Debido a que el ácido se disocia en agua para producir los iones CH₃CHOHCOO⁻ y H₃O⁺ de igual manera (según la reacción (1)), tenemos:

[CH₃CHOHCOO⁻] = [H₃O⁺] = 1.78x10⁻³ M

Y por esa misma disociación, la concentración del ácido en el equilibrio es:

[tex] [CH_{3}CHOHCOOH^{-}] = 0.025 M - 1.78 \cdo 10^{-3} M = 0.023 M [/tex]

Entonces, la constante de equilibrio Ka del ácido láctico es:

[tex] Ka = \frac{[CH_{3}CHOHCOOH^{-}][H_{3}O^{+}]}{[CH_{3}CHOHCOOH]} = \frac{(1.78 \cdo 10^{-3})^{2}}{0.023} = 1.38 \cdot 10^{-4} [/tex]          

Espero que te sea de utilidad!