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3 years ago

Which statement are true about producers?

Chemistry

1 answer:

Mamont248 [21]3 years ago

3 0

A, B, C, D

I'm not too sure about C though because sometimes producers are the base of food webs and other times its just the sun. Sorry if I wasn't much help

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Calculate the pH in titration of a weak acid: What is the pH in titration of formic acid (HCHO2, 0.200 M, 100.0 mL) after the ad

ki77a [65]

Answer:

pH = 12.61

Explanation:

First of all, we determine, the milimoles of base:

0.120 M = mmoles / 300 mL

mmoles = 300 mL . 0120 M = 36 mmoles

Now, we determine the milimoles of acid:

0.200 M = mmoles / 100 mL

mmoles = 100 mL . 0.200M = 20 mmoles

This is the neutralization:

HCOOH + OH⁻ ⇄ HCOO⁻ + H₂O

20 mmol 36 mmol 20 mmol

16 mmol

We have an excess of OH⁻, the ones from the NaOH and the ones that formed the salt NaHCOO, because this salt has this hydrolisis:

NaHCOO → Na⁺ + HCOO⁻

HCOO⁻ + H₂O ⇄ HCOOH + OH⁻ Kb → Kw / Ka = 5.55×10⁻¹¹

These contribution of OH⁻ to the solution is insignificant because the Kb is very small

So: [OH⁻] = 16 mmol / 400 mL → 0.04 M

- log [OH⁻] = pOH → 1.39

pH = 14 - pOH → 12.61

6 0

3 years ago

Why does warm air raise and cold air sink

ki77a [65]

Warm is less heaver then cold air so warm air rise and cold air sinks

3 0

3 years ago

Read 2 more answers

The Ka of hydrazoic acid (HN3) is 1.9 × 10-5 at 25.0 °C. What is the pH of a 0.40 M aqueous solution of HN3?

siniylev [52]

Answer:

The pH of the solution is 2.56.

Explanation:

Given :

Concentration (c) = 0.40 M

Acid dissociation constant = $K_a=1.9\times 10^{-5}$

The equilibrium reaction for dissociation of $HN_3$ (weak acid) is,

$HN_3+H_2O\rightleftharpoons N_3^{-}+H_3O^+$

initially conc. c 0 0

At eqm. $c(1-\alpha)$ $c\alpha$ $c\alpha$

Dissociation constant is given as:

$K_a=\frac{(c\alpha)(c\alpha)}{c(1-\alpha)}$

$1.9\times 10^{-5}=\frac{(0.40\alpha)(0.40\alpha)}{0.40(1-\alpha)}$

By solving the terms, we get value of $(\alpha)}$

$\alpha=0.00686832$

No we have to calculate the concentration of hydronium ion or hydrogen ion.

$[H^+]=c\alpha=0.4\times 0.00686832=0.002747 M$

Now we have to calculate the pH.

$pH=-\log [H^+]$

$pH=-\log (0.002747)$

$pH=2.56$

Therefore, the pH of the solution is, 2.56.

8 0

4 years ago

The most common form of energy encountered in chemical reactions is _____. Select one:

Svetllana [295]

The answer is b heat

3 0

3 years ago

Combustion reaction all follow a similar pattern, complete the work equation below

ruslelena [56]

<span>Hydrocarbon + Oxygen → Carbon dioxide + Water</span>

6 0

3 years ago