I dunno which one it is could someone help please?

Chemistry

2 answers:

mars1129 [50]3 years ago

8 0

B. Photosynthesis

Oxygen and glucose make perfect energy for plants

alex41 [277]3 years ago

5 0

Answer: B. photosynthesis

Explanation: Glucose and oxygen react together in plant cells to produce energy.

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A compound has been shown to contain 14.5 percent hydrogen and 85.5 percent carbon by mass.

Sedaia [141]

Answer:

Option d. Its empirical formula is CH₂.

Explanation:

The percent composition of the compound allow you to calculate the empirical formula of the compound but is not enough to calculate either the molar mass or the molecular formula. So, since now you can discard options b. and c.

Telling that it is a hydrocarbon (option e.) is true but very vague compared with finding the empirical formula. So, you can also discard the option e.

The fact that the product has a triple bond cannot be concluded from the percent composition, you should find the molecular formula to assert whether it contains or not a triple bond. So, you could discard option a., which lets you only with choice d.

Let us find the empirical formula to be certain that it is CH₂.

1. First, assume a basis of 100 g of compound:

H: 14.5% × 100 g = 14.0 g

C: 85.5% × 100 g = 85.5 g

2. Divide each element by its atomic mass to find number of moles:

H: 14.0 g / 1.008 g/mol = 14.38 mol

C: 85.5 g / 12.011 g/mol = 7.12 mol

3. Divide both amounts by the smallest number, to find the mole ratio:

H: 14.38 mol / 7.12 mol ≈ 2
C: 7.12 mol / 7.12 mol = 1.

Hence, the ratio is 2:1 and the empirical formula is CH₂.

7 0

3 years ago

How much heat does a 100. g sample of copper absorb when its temperature increases by 30.0°C? The specific heat of copper is 0.3

erica [24]

Answer:

$\boxed {\boxed {\sf B. \ 1170 \ Joules }}$

Explanation:

We are asked to find how much heat a sample of copper absorbs when the temperature is increased.

Since we know the mass, temperature increase, and specific heat capacity, we can use the following formula to calculate heat.

$q= mc \Delta T$

The mass of the copper sample is 100 grams, the temperature is changed or increased by 30.0 degrees Celsius, and the specific heat of copper is 0.39 Joules per gram degrees Celsius.