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4 years ago

True or false: scientists make observations very carefully science

Chemistry

2 answers:

posledela4 years ago

8 0

True hope this helped u

Olenka [21]4 years ago

3 0

True, scientists do make observations very carefully.

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The balance of the following equations

myrzilka [38]

A. 6 NaOH + 2(NH4)3 PO4 -----> 2Na PO4 + 6H2O + 6NH3

b. C2 H6 O + 3O2 ----> 2CO2 + 3H2O

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3 years ago

What effect would a decrease or increase in barometric pressure have on the boiling point

sladkih [1.3K]

Answer:

Pressure Affects the Boiling Point

Atmospheric pressure influences the boiling point of water. When atmospheric pressure increases, the boiling point becomes higher, and when atmospheric pressure decreases (as it does when elevation increases), the boiling point becomes lower.

Explanation:

i think it will help you

5 0

3 years ago

26 g of zinc combines with 12.8 g of sulfur. What is the empirical formula of zinc sulfide?

Alisiya [41]

Moles of Zn: 26 / 65 = 0.4
Moles of S: 12.8 / 32 = 0.4

Molar ratio of Zn : S = 1 : 1
Empircal formula: ZnS

The answer is C

7 0

4 years ago

6 State Your Claim Make a claim about how you<br> could separate a mixture of rocks and sand.

Sloan [31]

Answer: Sand can be separated from the sand by the process of Sieving. sorry if I'm wrong please give me brainlest

Explanation:

4 0

2 years ago

Given the following data:

bagirrra123 [75]

$176.0 \; \text{kJ} \cdot \text{mol}^{-1}$

As long as the equation in question can be expressed as the sum of the three equations with known enthalpy change, its $\Delta H$ can be determined with the Hess's Law. The key is to find the appropriate coefficient for each of the given equations.

Let the three equations with $\Delta H$ given be denoted as (1), (2), (3), and the last equation (4). Let $a$ , $b$ , and $c$ be letters such that $a \times (1) + b \times (2) + c \times (3) = (4)$ . This relationship shall hold for all chemicals involved.

There are three unknowns; it would thus take at least three equations to find their values. Species present on both sides of the equation would cancel out. Thus, let coefficients on the reactant side be positive and those on the product side be negative, such that duplicates would cancel out arithmetically. For instance, $3 + (-1) = 2$ shall resemble the number of $\text{H}_2$ left on the product side when the second equation is directly added to the third. Similarly

$\text{NH}_4 \text{Cl} \; (s)$ : $-2 \; a = 1$
$\text{NH}_3\; (g)$ : $-2 \; b = -1$
$\text{HCl} \; (g)$ : $2 \; c = -1$

Thus

$a = -1/2\\b = 1/2\\c = -1/2$ and

$-\frac{1}{2} \times (1) + \frac{1}{2} \times (2) - \frac{1}{2} \times (3)= (4)$

Verify this conclusion against a fourth species involved- $\text{N}_2 \; (g)$ for instance. Nitrogen isn't present in the net equation. The sum of its coefficient shall, therefore, be zero.

$a + b = -1/2 + 1/2 = 0$

Apply the Hess's Law based on the coefficients to find the enthalpy change of the last equation.

$\Delta H _{(4)} = -\frac{1}{2} \; \Delta H _{(1)} + \frac{1}{2} \; \Delta H _{(2)} - \frac{1}{2} \; \Delta H _{(3)}\\\phantom{\Delta H _{(4)}} = -\frac{1}{2} \times (-628.9)+ \frac{1}{2} \times (-92.2) - \frac{1}{2} \times (184.7) \\\phantom{\Delta H _{(4)}} = 176.0 \; \text{kJ} \cdot \text{mol}^{-1}$

3 0

3 years ago