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3 years ago

What are three observable changes that show a chemical reaction?

Chemistry

1 answer:

adoni [48]3 years ago

5 0

Answer:

Fizzing, New color, and odor

Explanation:This is because chemicals change the smell which can be called odor, chemicals change the color, and when something is fizzing their is a chemical reaction going on.

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Use a Punnett square to predict the cross of a homozygous tall parent with a homozygous short parent, if tall is dominant over s

ycow [4]

Answer:

All offspring are tall when a homozygous tall parent with homozygous short parent.

Explanation:

When we crossed homozygous tall parent with homozygous short parent, we conclude that all offspring are tall, because homozygous short parent are supressed under the homozygous tall parent, due to law of dominance.

Law of dominance states that, recessive alleles are suppressed by dominant alleles but they can appear in F2 generation.

Using a punett square, we can predict the cross between homozygous tall and homozygous short parent.

The phenotypes are: All are tall plants (4:0).

5 0

3 years ago

CaC2(s) + 2H2O(l) --> Ca(OH)2(aq) + C2H2(g) In the reaction above, 0.5487 grams of calcium carbide are completely consumed to

jasenka [17]

Answer:

239.7mL

Explanation:

Using the general gas equation;

PV = nRT

Where;

P = pressure (atm)

V = volume (L)

n = number of moles (mol)

R = gas constant (0.0821 Latm/molK)

T = temperature (K)

The balanced chemical equation in this question is as follows:

CaC2(s) + 2H2O(l) --> Ca(OH)2(aq) + C2H2(g)

From the equation, 1 mole of CaC2 produces 1 mole of ethylene gas, C2H2.

Using mole = mass/molar mass

Molar mass of CaC2 = 40 + 12(2)

= 40 + 24

= 64g/mol

mole = 0.5487/64

mole = 0.00857mol of CaC2

Hence, 0.00857mol of CaC2 produced 0.00857mol of C2H2

Based on the information provided, n = 0.00857mol, T = 43°C = 43 + 273 = 316K, p = 0.926 atm

PV = nRT

V = nRT/P

V = 0.00857 × 0.0821 × 316/0.926

V = 0.222/0.926

V = 0.2397L

In mL, volume = 0.2397 × 1000

= 239.7mL

3 0

2 years ago

Which characteristic might identify a substance as an Arrhenius base?

Scorpion4ik [409]

Answer: a

Explanation: because an Arrhenius acid is a compound that increases the H + ion concentration in aqueous solution. An Arrhenius base is a compound that increases the OH − ion concentration in aqueous solution.

5 0

3 years ago

Read 2 more answers

When 0.250 moles of KCl are added to 200.0 g of water in a constant pressure calorimeter a temperature change is observed. Given

777dan777 [17]

Explanation:

Upon dissolution of KCl heat is generated and temperature of the solution raises.

Therefore, heat generated by dissolving 0.25 moles of KCl will be as follows.

$17.24 kJ/mol \times 0.25 mol$

= 4.31 kJ

or, = 4310 J (as 1 kJ = 1000 J)

Mass of solution will be the sum of mass of water and mass of KCl.

Mass of Solution = mass of water + (no. of moles of KCl × molar mass)

= 200 g + $(0.25 mol \times 54.5 g/mol)$

= 200 g + 13.625 g

= 213.625 g

Relation between heat, mass and change in temperature is as follows.

Q = $mC \Delta T$

where, C = specific heat of water = $4.184 J/g^{o}C$

Therefore, putting the given values into the above formula as follows.

Q = $mC \Delta T$

4310 J = $213.625 g \times 4.184 J/g^{o}C \times \Delta T$

$\Delta T = 4.82^{o}C$

Thus, we can conclude that rise in temperature will be $4.82^{o}C$ .

6 0

3 years ago

Which compound can act as both a Bronsted-Lowry acid and a Bronsted-Lowry base?

Dvinal [7]

The answer is A. Water

Bronsted-Lowry base compounds are those that can accept protons

Bronsted-Lowry Acid Compounds are those that can recieve one

Water / H2O is an Amphoteric compund which mean that its molecul can act as a Base and Acid compound, so the answer is A.

5 0

2 years ago