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2 years ago

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According to the law of conservation of matter, the number of ________ is not changed by a chemical reaction. A. molecules B. at

oms C. bonds D. products

2 answers:

laila [671]2 years ago

7 0

The answer is B. atoms

fiasKO [112]2 years ago

3 0

Answer:

ATOMS

Explanation:

STUDY ISLAND

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In a spacecraft tge carbon dioxide exhaled by the astronaut can be removed by the reaction with lithium hydroxide, LiOH accordin

quester [9]

Answer:

30 moles

Explanation:

From the equation it is a one - to - one reaction

3 0

2 years ago

15.0 mL of an unknown clear liquid is added to a 50 mL graduated cylinder. The mass of the liquid is determined to be 12.7 grams

sveticcg [70]

Answer:

$\boxed {\tt A. \ d=0.85 \ g/mL}$

Explanation:

Density is found by dividing the mass by the volume.

$d=\frac{m}{v}$

The mass of the liquid is 12.7 grams.

We know that 15 mL of this liquid was added to a 50 mL graduated cylinder. Therefore, the volume is 15 mL. The 50 mL is not relevant, it only tells us about the graduated cylinder.

$m= 12.7 \ g\\v= 15 \ mL$

Substitute the values into the formula.

$d=\frac{12.7 \ g}{ 15 mL}$

Divide.

$d=0.846666667 \ g/mL$

Round to the nearest hundredth. The 6 in the tenth place tells us to round the 4 to a 5.

$d \approx 0.85 \ g/mL$

The density of the liquid is about 0.85 grams per milliliter and choice A is correct.

4 0

3 years ago

In the forward reaction of this equilibrium, which substance acts as the brønsted-lowry base? h2s(aq)+ch3nh2(aq)⇋hs−(aq)+ch3nh+3

spin [16.1K]

<span>Answer: Bronsted base is something that accepts proton (H+) and acid is something that donates H+ so here CH3NH2 will be the base and H2S is the acid.</span>

7 0

3 years ago

2Mg + O2 → 2MgO<br><br> If you are burning 5.8332 g of Mg, how many grams of MgO will this make?

LekaFEV [45]

<h3>Answer:</h3>

9.6724 g MgO

<h3>General Formulas and Concepts:</h3>

<u>Math</u>

<u>Pre-Algebra</u>

Order of Operations: BPEMDAS

Brackets
Parenthesis
Exponents
Multiplication
Division
Addition
Subtraction

Left to Right

<u>Chemistry</u>

<u>Stoichiometry</u>

Reading a Periodic Table
Using Dimensional Analysis

<h3>Explanation:</h3>

<u>Step 1: Define</u>

[RxN - Balanced] 2Mg + O₂ → 2MgO

[Given] 5.8332 g Mg

<u>Step 2: Identify Conversions</u>

[RxN] 2 mol Mg = 2 mol MgO

Molar Mass of Mg - 24.31 g/mol

Molar Mass of O - 16.00 g/mol

Molar Mass of MgO - 24.31 + 16.00 = 40.31 g/mol

<u>Step 3: Stoichiometry</u>

Set up: $\displaystyle 5.8332 \ g \ Mg(\frac{1 \ mol \ Mg}{24.31 \ g \ Mg})(\frac{2 \ mol \ MgO}{2 \ mol \ Mg})(\frac{40.31 \ g \ MgO}{1 \ mol \ MgO})$
Multiply/Divide: $\displaystyle 9.67241 \ g \ MgO$

<u>Step 4: Check</u>

<em>Follow sig fig rules and round. We are given 5 sig figs.</em>

9.67241 g MgO ≈ 9.6724 g MgO

5 0

3 years ago

Read 2 more answers

an element "x" has the election configuration 2,8,3 this element is found in ______group and_____period A.3,llla B.llla,3 C.vlla

iogann1982 [59]

This element is found in group 3A, period 3

<h3>Further explanation </h3>

The maximum number of electrons that can be filled in the nth electron shell is 2n²(n=shell)

K shell (n = 1) maximum 2 x 1² = 2 electrons

L shell (n = 2) maximum 2 x 2² = 8 electrons
M shell (n = 3) maximum 2 x 3² = 18 electrons
N shell (n = 4) maximum 2 x 4² = 32 electrons

Electron configuration of element X : 2.8.3 , so :

K shell = 2 ⇒1s²

L shell = 8⇒2s²2p⁶

M shell = 3⇒ 3s²3p¹

Block p: group 13-18 (has a 2p-6p configuration), also called a representative element because it includes metals, non-metals and metalloids

The outer shell 3s²3p¹ : located in group 3A and period 3

group⇒valence electron ⇒3

period⇒the greatest value of the quantum number n⇒3

3 0

3 years ago