A laboratory assistant was experimenting with chemical reactions when she combined a small amount of zinc (Zn) with hydrochloric acid (HCl). She discovered that zinc chloride (ZnCl2) [2 should be small and below the Cl] and hydrogen (H2) [2 should be small and below the H] were produced. Which of the following substances are the reactants? PLEASE PLEASE NO LINKS
A. Zn + HCl
B. ZnCl2 + H2
C. Zn + H2
D. ZnCl2 + HCl

the movement of aircraft through clouds can even cause lightning strikes. a single lightning event is a "flash", which is a complex, multi-stage explosively ejected.

explanation:

and the person below goggled it.

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i'm assuming that the correct answer is indeed the first one/ "a"..

when 25.0 ml of 0.700 mol/l naoh was mixed in a calorimeter with 25.0 ml of 0.700 mol/l hcl, both initially at 20.0 °c, the temperature increased to 22.1 °c. the heat capacity of the calorimeter is 279 j/°c.

the equation for the reaction is:

naoh + hcl → nacl + h₂o

moles of hcl = 0.0250 l hcl ×

0.700

mol hcl

1 l hcl = 0.0175 mol hcl

volume of solution = (25.0 + 25.0) ml = 50.0 ml

mass of solution = 50.0 ml soln ×

1.00

ml soln

= 50.0 g soln

δt=t2-t1

= (22.1 – 20.0) °c = 2.1 °c

the heats involved are

heat from neutralization + heat to warm solution + heat to warm calorimeter = 0

q1+q2+q3=0

nδh+mcδt+cδt=0

0.0175 mol ×

δh

+ 50.0 g × 4.184 j·g⁻¹°c⁻¹ × 2.1 °c + 279 j°c⁻¹ × 2.1 °c = 0

0.0175 mol ×

δh

+ 439.32 j + 585.9 j = 0

0.0175 mol ×

δh

= -1025.22 j

δh=1025.22j0.0175 mol= -58 600 j/mol = -58.6 kj/mol

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health implications of pesticides

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other important considerations

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