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kolbaska11 [484]
3 years ago
13

Energy is involved in some way in all chemical reactions. Which type of reaction involves the absorption of energy from the surr

oundings? Options: exothermic reactions endothermic reactions
Chemistry
1 answer:
storchak [24]3 years ago
5 0

Answer:

endothermic reaction

Explantion:

The definition for endothermic is:

describing a process that involves the absorption of energy from the surroundings by substances undergoing change.

Think of <em>en-</em>dothermic as energy entering and <em>ex-</em>othermic as energy exiting.

You might be interested in
All formulas of mole concept​
aleksley [76]

Answer:

1 mole of substance to be 6.022 × 1023

Explanation:

thats all i could come up with

3 0
3 years ago
A 0.271g sample of an unknown vapor occupies 294ml at 140C and 874mmHg. The emperical formula of the compound is CH2. How many m
Phoenix [80]
Using PV = nRT, we can calculate the moles of the sample.
874 mmHg = 116,524 Pa
n = PV/RT
n = 116,524 x 294 x 10⁻⁶ / 8.314 x (140 + 273)
n = 9.98 x 10⁻³ mol

moles = mass / Mr
Mr = 0.271/9.98 x 10⁻³
Mr = 27.2
Mass of empirical formula = 14
Repeat units = 27.2 / 14 ≈ 2

Formula of substance:
C₂H₄

Combustion equation:
C₂H₄ + 3O₂ → 2CO₂ + 2H₂O

1 mole produces 2 moles of CO₂, so 3 moles will produce 6 moles CO₂
7 0
3 years ago
You drop a rock weighing 23.2 g into a graduated cylinder that contains 55 mL. The level of the water rises to 62 mL. What is th
ra1l [238]

The density of the rock is 3.314g/mL

CALCULATE DENSITY:

  • According to this question, a rock weighs 23.2g. After dropping the rock into a graduated cylinder containing 55mL of water, the level changes to 62mL.

  • This means that the volume of the rock can be calculated as follows:

Volume of rock = 62mL - 55mL

Volume of rock = 7mL

Density can be calculated using the formula as follows:

Density = mass ÷ volume

Density = 23.2 ÷ 7

Density = 3.314g/mL

Therefore, the density of the rock is 3.314g/mL

Learn more: brainly.com/question/6034174?referrer=searchResults

4 0
3 years ago
Andi performs the calculation that is shown below.
rodikova [14]

Answer: 3.59

Explanation:

(2.06)(1.743)(1.00)

2.06 × 1.743 × 1.00

= 3.59058

Two of the multiplied digits are represented in 3 significant figures. Therefore, for correct representation, the result of the product should be written to three significant figures.

3.59058 to 3 significant figures:

First three digits = 3.59

Fourth digit '0' is less than 5, and thus rounded to 0 with other succeeding digits

Therefore, (2.06)(1.743)(1.00) to 3 significant figures equals :

3.59

3 0
3 years ago
The following five beakers, each containing a solution of sodium chloride (NaCl, also known as table salt), were found on a lab
mixas84 [53]

Answer:

See the answers below

Explanation:

1)  100. mL of solution containing 19.5 g of NaCl  (3.3M)

2)  100. mL of 3.00 M NaCl solution (3 M)

3) 150. mL of solution containing 19.5 g of NaCl  (2.2 M)

4)  Number 1 and 5 have the same concentration (1.5M)

MW of NaCl = 23 + 36 = 59 g

For number 3

          59 g ------------------- 1 mol

           19,5 g -----------------   x

  x = 19.5 x 1/59 = 0.33 mol

Molarity (M) = 0.33 mol/0.150 l = 2.2 M

For number 4,

Molarity (M) = 0.33mol/0.10 l = 3.3 M

For number 5

Molarity (M) = 0.450/0.3 = 1.5 M

4 0
3 years ago
Read 2 more answers
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