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2 years ago

What is the atomic number of an element that has seven protons and eight neutrons and seven electrons?

Chemistry

2 answers:

Dmitrij [34]2 years ago

7 0

Answer:

Nitrogen has an atomic number of 7 (Z=7) because it has 7 protons in its nucleus. Some nitrogen atoms have an atomic mass number of 15 (A=15). A is the number of neutrons plus protons in the nucleus. However, we already know that there are 7 protons

Darya [45]2 years ago

6 0

Answer:

Atomic number = Number of protons = Number of electrons

Atomic number = 7

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The density of water is 1 g/cm3(1 gram per cubic centimeter); using this fact as a reference & Table c , how would you deter

NISA [10]

Answer:

Explanation:

Any densities less than 1g/cm3 will float, while objects with densities over 1g/cm3 will sink.

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2 years ago

What is the ratio of [a–]/[ha] at ph 2.75? the pka of formic acid (methanoic acid, h–cooh) is 3.75?

Varvara68 [4.7K]

The dissociation of formic acid is:

$HCOOH \rightleftharpoons HCOO^{-} + H^{+}$

The acid dissociation constant of formic acid, $k_a$ is:

$k_a = \frac{[HCOO^{-}] [H^{+}]}{HCOOH}$

Rearranging the equation:

$\frac{[HCOO^{-}]}{[HCOOH]} = \frac{k_a}{[H_+]}$

pH = 2.75

$pH = -log[H^{+}]$

$[H^{+}]= 10^{-2.75} = 1.78 \times 10^{-3}$

$pk_a = 3.75$

$k_a = 10^{-3.75} = 1.78\times 10^{-4}$

Substituting the values in the equation:

$\frac{[HCOO^{-}]}{[HCOOH]} = \frac{k_a}{[H_+]}$

$\frac{[HCOO^{-}]}{[HCOOH]} = \frac{1.78\times 10^{-4}}{1.78\times 10^{-3}}$

Hence, the ratio is $\frac{1}{10}$ .

4 0

2 years ago

Which term describes this reactions?

Salsk061 [2.6K]

Answer:

Elimination

Explanation:

Since they are removing water from the solution, it is called elimination.

5 0

2 years ago

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The diameter of a red blood cell is about 3 × 10−4 in. What is its diameter in centimeters?

lesantik [10]

Answer:

1 in. =2.54 cm

3*(10^-4)*2.54=7.62*10^-4

Explanation:

8 0

2 years ago

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Silver acetate breaks into ions. How many ions would one single formula unit make if dissolved in water? a. 1b. 2c. 3 d. 4 e. no

slava [35]

Answer:

The correct answer is b) 2

Explanation:

When is dissolved in water, silver acetate (AgCH₃COO) is dissociated into ions according to the following equilibrium:

AgCH₃COO ⇄ Ag⁺ + CH₃COO⁻

Where Ag⁺ is a silver cation and CH₃COO⁻ is the acetate anion (an organic anion). As we can see, from one single formula unit are obtained 2 ions (1 cation and 1 anion).

Therefore, the correct option is b) - 2

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2 years ago