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2 years ago

What do we call the stars whose properties follow the patterns?

Chemistry

1 answer:

muminat2 years ago

4 0

Answer:

It is called Asterism.

Explanation:

It is Asterism because Asterism refers to a pattern of stars that are seen in night sky and are very distinctive and identifiable. These group of starts have patterns. It visually seen collection of stars and it's indicate their properties and the lines that connect the stars together. It actually range from small shapes of stars to more complex stars that cover segment of the sky. The stars may be bright naked or have similar brightness.

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Why vitamin A(retinol) transported by chylomicrons ?

OLga [1]

Answer:

from the small intestine (RE = retinyl ester; ROH = ret- inol. CM = chylomicron remnant). is split at least one intact molecule of retinol, retinal.

4 0

2 years ago

What letter represents the enthalpy of reaction?

Anna35 [415]

Answer:

Option D. T

Explanation:

Enthalpy change (ΔH) is simply the difference between the heat content of the product (Hp) and the heat content of the reactant (Hr). Mathematically, it is expressed as:

Enthalpy change (ΔH) = Heat of product (Hp) – heat of reactant (Hr)

ΔH = Hp – Hr

From the diagram given above, the difference between the heat content of product and the heat content of reactant is T.

Therefore, the enthalpy change of the reaction is T.

5 0

3 years ago

139%

GaryK [48]

Answer:

The percent composition of this compound is 94%

Explanation:

The reaction can be formed as

$2 \mathrm{Fe}+3 \mathrm{Cl}_{2} \rightarrow 2 \mathrm{FeCl}_{3}$

$\frac{\text { Weight of } \mathrm{Cl}_{2}}{\text { 3* Molar Mass of } \mathrm{Cl}_{2}}=\frac{\text { Weight of } \mathrm{Fe}}{2 * \text { Molar Mass of Fe }}$

$\frac{\text { Weight of } \mathrm{Cl}_{2}}{3 *(2 * 35.5)}=\frac{3.56}{2 * 55.8}$

$\text { Weight of } C l_{2}=\frac{3.56 * 3 * 71}{2 * 55.8}=6.79 \mathrm{g}$

$\mathrm{n}\left(\mathrm{Cl}_{2}\right)=\mathrm{m}\left(\mathrm{Cl}_{2}\right) / \mathrm{M}\left(\mathrm{Cl}_{2}\right)=6.79 / 71=0.1 \mathrm{m}$

$\mathrm{n}(\mathrm{Fe})=\mathrm{m}(\mathrm{Fe}) / \mathrm{M}(\mathrm{Fe})=3.56 / 55.8=0.06 \mathrm{m}$

Based on no. of iron reacted,

$\mathrm{n}(\text { moles of } \mathrm{Fe})=\mathrm{n}\left(\text { moles of } \mathrm{FeCl}_{3}\right)$

n = m/M

$\mathrm{m}\left(\mathrm{FeCl}_{3}\right)=\mathrm{n}^{*} \mathrm{M}=0.06^{*} 162.5=9.75 \mathrm{g}$

% composition of $FeCl_3$

= $(9.75 / 10.39)^{*} 100$

= 94%

6 0

3 years ago

Predict the spontaneity of a reaction (and the temperature dependence of the spontaneity) for each possible combination of signs

Akimi4 [234]

Answer and Explanation:

At constant pressure and constant temperature, the Gibbs free energy of a process is given by the following equation:

ΔG= ΔH - T ΔS

The process is spontaneous when ΔG<0. For this, there are four alternatives depending on the signs of ΔH and ΔS and the temperature (T):

1) ΔH negative, ΔS positive ⇒ b)The reaction will be spontaneous at all temperatures.

ΔG= (-H) - T (+S) ⇒ ΔG<0 always

2) ΔH positive, ΔS negative ⇒ c)The reaction will be nonspontaneous at all temperatures.

ΔG= (+H) - T (-S) ⇒ ΔG>0 always

3) ΔH negative, ΔS negative ⇒ d)The reaction will be spontaneous at low temperature, but nonspontaneous at high temperature.

ΔG= (-H) - T (-S) ⇒ ΔG<0 if TΔS is lower than ΔH, because is the positive term

4)ΔH positive, ΔS positive ⇒ a)The reaction will be nonspontaneous at low temperature, but spontaneous at high temperature.

ΔG= (+H) - T (+S) ⇒ ΔG<0 if TΔS higher than ΔH because is the negative term

8 0

2 years ago

Given 5.0 grams of lead (II) nitrate and 3.0

natulia [17]

Answer:

1.70 g of NaNO₃

Explanation:

The balance chemical equation for given double displacement reaction is,

Pb(NO₃)₂ + 2 NaI → PbI₂ + 2 NaNO₃

Step 1: Calculate moles of each reactant:

Moles = Mass / M.Mass

For Pb(NO₃)₂:

Moles = 5.0 g / 331.21 g/mol

Moles = 0.0150 moles

For NaI:

Moles = 3.0 g / 149.89 g/mol

Moles = 0.020 moles

Step 2: Calculate Limiting reagent as;

According to equation,

1 mole of Pb(NO₃)₂ reacts with = 2 moles of NaI

So,

0.0150 moles of Pb(NO₃)₂ will react with = X moles of NaI

Solving for X,

X = 2 mol × 0.0150 mol / 1 mol

X = 0.030 moles of NaI

Hence, it means that NaI is the limiting reagent therefore, it will control the yield of Sodium Nitrate.

Step 3: Find out moles of NaNO₃ formed:

According to equation,

2 mole of NaI produced = 2 moles of NaNO₃

So,

0.020 moles of NaI will produce = X moles of NaNO₃

Solving for X,

X = 2 mol × 0.020 mol / 2 mol

X = 0.020 moles of NaNO₃

Step 4: Calculate Mass of NaNO₃ produced;

As, Moles = Mass / M.Mass

Or,

Mass = Moles × M.Mass

Putting values,

Mass = 0.020 mol × 84.99 g/mol

Mass = 1.70 g of NaNO₃

7 0

3 years ago