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miss Akunina [59]
2 years ago
11

Science please help me with this

Chemistry
2 answers:
nataly862011 [7]2 years ago
7 0

Answer:

a lack of genetic variety

first one is the correct one

kvv77 [185]2 years ago
6 0
A lack of genetic variety


The first one
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This table lists some characteristics of two planets.<br> Which statement is true?
LekaFEV [45]

gravity

Explanation:

gravity is the same in any planet

5 0
2 years ago
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What mass (in grams) of Mg(NO3)2 is present in 151 mL of a 0.350 M solution of Mg(NO3)2?
Mademuasel [1]

Answer is: A) 7.84 g.

V(Mg(NO₃)₂) = 151 mL ÷ 1000 mL/L.

V(Mg(NO₃)₂) = 0.151 L; volume of the magnesium nitrate.

c(Mg(NO₃)₂) = 0.352 M; molarity of the solution.

n(Mg(NO₃)₂) = V(Mg(NO₃)₂) · c(Mg(NO₃)₂).

n(Mg(NO₃)₂) ) = 0.151 L · 0.352 mol/L.

n(Mg(NO₃)₂) = 0.0531 mol; amount of the substance.

M(Mg(NO₃)₂) = Ar(Mg) + 2Ar(N) + 6Ar(O) · g/mol.

M(Mg(NO₃)₂) = 24.3 + 2·14 + 6·16 · g/mol.

M(Mg(NO₃)₂) = 148.3 g/mol; molar mass.

m(Mg(NO₃)₂) = n(Mg(NO₃)₂) · M(Mg(NO₃)₂).

m(Mg(NO₃)₂) = 0.0531 mol · 148.3 g/mol.

m(Mg(NO₃)₂) = 7.84; mass of magnesium nitrate.

6 0
3 years ago
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Answer A B C and D please for my chemistry hw
r-ruslan [8.4K]

<u>Answer:</u> The equations are provided below.

<u>Explanation:</u>

Skeleton equations are defined as the equations which simply indicate the molecules that are involved in a chemical reaction. These equations are unbalanced equations.

Balanced equations are defined as the chemical equation in which number of individual atoms on the reactant side must be equal to the number of individual atoms on the product side.

  • For A:

Water decomposes in the direct current to form hydrogen and oxygen.

Skeleton Equation: H_2O(l)\rightarrow H_2(g)+O_2(g)

Balanced Equation: 2H_2O(l)\rightarrow 2H_2(g)+O_2(g)

  • For B:

Mercury (II) oxide decomposes in heat to form mercury, oxygen.

Skeleton Equation: HgO(s)\rightarrow Hg+O_2

Balanced Equation: 2HgO(s)\rightarrow 2Hg+O_2

  • For C:

Calcium carbonate when heated forms calcium oxide and carbon dioxide.

Skeleton Equation: CaCO_3(s)\rightarrow CaO(s)+CO_2(g)

Balanced Equation: CaCO_3(s)\rightarrow CaO(s)+CO_2(g)

  • For D:

Group 2 hydroxides, when heated forms oxide and water vapor.

Skeleton Equation: Ca(OH)_2\rightarrow CaO+H_2O

Balanced Equation: Ca(OH)_2\rightarrow CaO+H_2O

3 0
3 years ago
During a combustion reaction, 9.00 grams of oxygen reacted with 3.00 grams of CH4.
Monica [59]

Answer:

0.74 grams of methane

Explanation:

The balanced equation of the combustion reaction of methane with oxygen is:

  • CH₄ + 2 O₂ → CO₂ + 2 H₂O

it is clear that 1 mol of CH₄ reacts with 2 mol of O₂.

firstly, we need to calculate the number of moles of both

for CH₄:

number of moles = mass / molar mass = (3.00 g) /  (16.00 g/mol) = 0.1875 mol.

for O₂:

number of moles = mass / molar mass = (9.00 g) /  (32.00 g/mol) = 0.2812 mol.

  • it is clear that O₂ is the limiting reactant and methane will leftover.

using cross multiplication

1 mol of  CH₄ needs → 2 mol of O₂

???  mol of  CH₄  needs → 0.2812 mol of O₂

∴ the number of mol of CH₄ needed = (0.2812 * 1) / 2 = 0.1406 mol

so 0.14 mol will react and the remaining CH₄

mol of CH₄ left over = 0.1875 -0.1406 = 0.0469 mol

now we convert moles into grams

mass of CH₄ left over = no. of mol of CH₄ left over *  molar mass

                                    = 0.0469 mol * 16 g/mol = 0.7504 g

So, the right choice is 0.74 grams of methane

3 0
3 years ago
An endothermic reaction has
pav-90 [236]
Sorry I don’t know the answer but sorry about this person
5 0
3 years ago
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