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3 years ago

Which set of coefficients will balance this chemical equation?

Chemistry

1 answer:

Katarina [22]3 years ago

7 0

Answer:

B 1,3

Explanation:

Count the atoms on each side of the arrow, they have to be equal

After arrow

2x C

6x O

4x H

Before the arrow

2x C - correct, as it is the only compound with C then there must only be 1 mole of it.

This is also the correct amount of H

We need 6x O total so 6/2 = 3

So there are 3 moles of O

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4. Solve the following heat flow problem, being sure to show all your work (you may either type your

Viktor [21]

Answer:

0.70 J/g.°C

Explanation:

Step 1: Given data

Mass of graphite (m): 402 g

Heat absorbed (Q): 1136 J

Initial temperature: 26°C

Final temperature: 30 °C

Specific heat of graphite (c): ?

Step 2: Calculate the specific heat of graphite

We will use the following expression.

Q = c × m × ΔT

c = Q / m × ΔT

c = 1136 J / 402 g × (30°C - 26°C)

c = 0.70 J/g.°C

5 0

3 years ago

An electron in a hydrogen atom relaxes to the n=4 level, emitting light of 74 THz.

Solnce55 [7]

Delta E = Ef - Ei
E = energy , h = plank constant , v = frequency
h= 6.626 * 10 ^-34 j*s , T = 10 ^ 12 , v = 74 * 10 ^12 Hz , Hz = s^-1

E = ( 6.626 * 10^ -34 j*s) ( 74 * 10 ^ 12 s^ -1 ) = 4.90 * 10 ^ -20 J
Delta E = Ef - Ei
-4.90 * 10 ^ -20 J = -2.18 * 10 ^ -18J ( 1/4 ^2 - 1/x ^2)
0.0225 = 0.0625 - ( 1/x ^ 2)
0.225 - 0.0625 = - 1/ x ^ 2

- 0.0400 = - 1/x ^2 = -1 / - 0.0400 = x^2
25 = x^2
x = 5

6 0

3 years ago

What is the mass of solute in a 500 mL solution of 0.200 M

Fofino [41]

16.4 grams is the mass of solute in a 500 mL solution of 0.200 M .

sodium phosphate

Explanation:

Given data about sodium phosphate

atomic mass of Na3PO4 = 164 grams/mole

volume of the solution = 500 ml or 0.5 litres

molarity of sodium phosphate solution = 0.200 M

The formula for molarity will be used here to know the mass dissolved in the given volume of the solution:

The formula is

molarity = $\frac{number of moles of solute}{volume in litres}$

putting the values in the equation, we get

molarity x volume = number of moles

0.200 X 0.5= number of moles

number of moles = 0.1 moles

Atomic mass x number of moles = mass

putting the values in the above equation

164 x 0.1 = 16.4 grams

16.4 grams of sodium phosphate is present in 0.5 L of the solution to make a 0.2 M solution.

8 0

3 years ago

(WILL GIVE BRAINLIEST) A student uses res litmus paper to test the pH value of different solutions. Which would result in a colo

Len [333]

Answer:

Soap & Drain Cleaner

Explanation:

3 0

3 years ago

I am having trouble predicting this equation. "Coke will reduce hot arsenious oxide to pure arsenic (As4). With the 4 as the sub

Rudik [331]

Well, Coke is just carbon in chemical reaction, so I think you get: 3 C + 2 As2O3--> 4 As + 3 CO2. Hope this helps! :)

7 0

3 years ago