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worty [1.4K]
3 years ago
15

SCIENCE ANSWER ASAP PLEASE!!

Chemistry
1 answer:
lara [203]3 years ago
4 0

Answer:

the question is not clearly seen

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A simple machine produces 25 joules of output work for every 50 joules of input work . What is the efficiency of this machine ?
nataly862011 [7]
2:1, output is half the input
8 0
3 years ago
Using the equations 2 Sr(s) + O₂ (g) → 2 SrO (s) ∆H° = -1184 kJ/mol SrO (s) + CO₂ (g) → SrCO₃ (s) ∆H° = -234 kJ/mol CO₂ (g) → C(
kkurt [141]

<u>Answer:</u> The \Delta H^o_{rxn} for the reaction is 72 kJ.

<u>Explanation:</u>

Hess’s law of constant heat summation states that the amount of heat absorbed or evolved in a given chemical equation remains the same whether the process occurs in one step or several steps.

According to this law, the chemical equation is treated as ordinary algebraic expressions and can be added or subtracted to yield the required equation. This means that the enthalpy change of the overall reaction is equal to the sum of the enthalpy changes of the intermediate reactions.

The given chemical reaction follows:

2SrCO_3(s)\rightarrow 2Sr(s)+2C(s)+3O_2(g)      \Delta H^o_{rxn}=?

The intermediate balanced chemical reaction are:

(1) 2Sr(s)+O_2(g)\rightarrow 2SrO(s)    \Delta H_1=-1184kJ

(2) SrO(s)+CO_2(g)\rightarrow SrCO_3(s)     \Delta H_2=-234kJ      ( × 2)

(3) CO_2(g)\rightarrow C(s)+O_2(g)     \Delta H_3=394kJ    ( × 2)

The expression for enthalpy of the reaction follows:

\Delta H^o_{rxn}=[1\times (\Delta H_1)]+[2\times (-\Delta H_2)]+[2\times (\Delta H_3)]

Putting values in above equation, we get:

\Delta H^o_{rxn}=[(1\times (-1184))+(2\times -(-234))+(2\times (394))]=72kJ

Hence, the \Delta H^o_{rxn} for the reaction is 72 kJ.

4 0
3 years ago
The brightness of a star depends on its _____ a. color b. composition of atmosphere c. distance from Earth, and stars that are c
Yanka [14]

Answer:

Either B or C. Composition or the Distance from the Earth.

5 0
3 years ago
HELP ME AND PLZ ANSWERED THIS ALL RIGHT PLZ
Sunny_sXe [5.5K]
<h2>Question no 1:</h2><h2>Answer:</h2>

The correct answer is option A which is Sarah is correct because genetic diversity occurs over a long period of time.

<h3>Explanation:</h3>
  • Genetic diversity is a large number of allelic combinations for a trait in specie in a population.
  • Genetic diversity is caused due to mutations or random breeding in a specie.
  • It is good for the adaptation of specie in an environment, due to diverse in genotypes and phenotype of a trait.
<h2>Question number 2:</h2><h2>Answer:</h2>

The correct answer is option B which is the species will adapt to the changes.

<h3>Explanation:</h3>
  • Adaptation to an environment means changing your body in such a way to reduce the harmful affects of changing the environment on the body.
  • For example, the long and thick fur of sheeps in a snowy area will protect them from cold.
  • If the environment changes, the first thing a specie do is an adaptation to that change in the environment.
<h2>Question 3.</h2><h2>Answer:</h2>

The correct answer is option D which is, "The spines of a cactus protect it from animals".

<h3>Explanation:</h3>
  • Adaptation to an environment means changing your body in such a way to reduce the harmful affects of changing the environment on the body.
  • For example, the long and thick fur of sheeps in a snowy area will protect them from cold.
  • So the plant of cactus was in danger due to animals. So the start growing spines in response to animals.
  • Hence the correct answer is option D.
<h2>Question 4.</h2><h2>Answer:</h2>

The correct answer is option B which is, "Marie's plant will lean toward the sun so that it can get the most sunlight".

<h3>Explanation:</h3>
  • The plant will lean towards the sun light by the mechanism of phototropism.
  • Phototropism is the mechanism of growth of the plant in a specific direction in the response of light.
  • There are two types of phototropism.
  • One is a positive phototropism in which plant grows towards the light.
  • The other is negative phototropism in which plant grows away from the light.
  • In this question,the plant will do positive tropism.
<h2>Question no. 5</h2><h2>Answer:</h2>

The correct answer is option B which is, "The dodo bird could not adapt quickly to the challenges of the environment".

<h3>Explanation:</h3>
  • Adaptation to an environment means changing your body in such a way to reduce the harmful affects of changing the environment on the body.
  • For example, the long and thick fur of sheeps in a snowy area will protect them from cold.
  • So the dodo could not adopt to the environment. For the positive adaption of survival, they should be afraid of sailors but the would not afraid of a sailor.
  • Due to which they went extinct.

Remaining questions are in attached document.






Download pdf
7 0
3 years ago
Scientists claim to be the way the continents were arranged 250 million years ago. Scientists who make this claim call this anci
Mkey [24]

Answer:

I dn't mnoefbv

Explanation:

Gr

6 0
2 years ago
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