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klemol [59]
3 years ago
5

How many ways can you choose ten tadpoles from a pool of 20

Chemistry
1 answer:
Georgia [21]3 years ago
5 0
Take half the amount
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Muscle tissue

Explanation: Muscle tissue is a soft tissue that makes up most of the tissues in the muscles of the human muscular system. It is the only type of tissue that has cells with the ability to contract. Skeletal muscle tissue is attached to bones by tendons.
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A sample of black coffee was measured to have [h3o+] = 7.94 × 10−6. what is true about this solution?
Sveta_85 [38]
Being given the hydronium (or simply the hydrogen) ion concentration (molarity), one of the easiest properties of the solution to determine is its pH. The pH of a solution indicates the acidity (or basicity) of a given solution. The typical pH range of solutions is from 1 to 14, with 7 being neutral, 1 to 6 being acidic, and 8 to 14 being basic. 

To determine the pH of a solution, the negative log (-log) of the hydronium/hydrogen ion concentration (molarity) of the solution is calculated. Thus (assuming that the given hydrogen ion concentration is in molarity (mol/L)),

             pH = -log(H^{+})          or          -log(H_{3} O^{+}
             pH = -log (<span>7.94 × 10−6 mol/L) 
             pH = 5.13

Because the pH is less than 7 (within the range 1 to 6), then the black coffee solution is acidic. </span>
6 0
3 years ago
A pound is approximately 0.45 kilogram. A person weighs 87 kilograms. What is the person’s weight, in pounds, when expressed to
Sauron [17]

Answer:

87 kilograms =191.8 pounds

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3 years ago
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Why are little pieces of cardboard lighter than a whole piece of cardboard?
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Predict the sign of ΔS° for 2NO2(g) LaTeX: \longrightarrow⟶ N2O4(g) CaCO3(s) + 2HCl(aq) LaTeX: \longrightarrow⟶ CaCl2(aq) + H2O(
prisoha [69]

Answer: a. 2NO_2(g)\rightarrow N_2O_4(g): \Delta S is negative

b. CaCO_3(s)+2HCl(aq)\rightarrow CaCl_2(aq)+H_2O(l) : \Delta S is negative

c. Ag^+(aq)+Cl^-(aq)\rightarrow AgCl(s): \Delta S is negative

Explanation:

Entropy is the measure of randomness or disorder of a system. If a system moves from  an ordered arrangement to a disordered arrangement, the entropy is said to decrease and vice versa

a)  2NO_2(g)\rightarrow N_2O_4(g)

In this reaction 2 moles of gaseous reactants are converting to 1 mole of gaseous products. The randomness will decrease and hence entropy will also decrease. Thus \Delta S is negative.

b) CaCO_3(s)+2HCl(aq)\rightarrow CaCl_2(aq)+H_2O(l)

In this reaction solid reactants are converting to aqueous products. The randomness will increase and hence entropy will also increase. Thus \Delta S is positive.

c) Ag^+(aq)+Cl^-(aq)\rightarrow AgCl(s)

In this reaction aqueous reactants are converting to solid products. The randomness will decrease and hence entropy will also decrease. Thus \Delta S is negative

3 0
3 years ago
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